Getting an android device to run without spyware will not be easy.
Let's face it, getting a spyware free android device is hard and will take a lot of work. 90% of all free applications available for android are spyware according to statistical data and all phones come shipped with spyware preinstalled. All phones come with Google software which itself is spyware and many manufacturers intentionally install their own spyware and remain silent about it until the general public learns about it. After that third parties could install their own spyware. Hell, even many of the programs that are supposed to be private collect data on you or allow Google to use them to collect data.
So, what can be done about it? Well, you would have to take risks and make compromises...
THE POTENTIALLY DANGEROUS PART, ONLY DO THIS IF YOU ARE CONFIDENT
If you can do so and seek to remove spyware, I highly recommend rooting your phone (this is optional). Why? Well, first of all most phones use google's dns server by default, you can change the dns server using root level software. You can also install a root level firewall and ad blockers. You can also use a program called stop services and disable some tracking services in apps with it. WARNING: ALWAYS BACK UP THE CURRENT SETTINGS IN STOP SERVICES BEFORE YOU USE IT AND KEEP TRACK OF WHAT YOU DISABLE! YOU MIGHT ACCIDENTALLY DISABLE MORE THAN JUST TRACKING SERVICES IN THE APPS! Of course, first make sure the manufacturer gives instructions on how to do so and follow them to the letter. Also, make sure there is a compatible version of TWRP for your phone and you back up everything on it first just in case something goes wrong. Also, makre sure to do your research, many one click rooting apps for your phone and windows programs you can use to root your phone will install hidden root level spyware if you use them. Doing research will help you to determine whether or not a rooting program will do so. Also, the moment you unlock the bootloader on your phone the warranty on it is voided.
OK, so you choose not to root your device? Well, you can install a custom firmware that lacks spyware if there is one compatible with your device (this is also optional and just as risky as rooting and yes, you must first unlock the bootloader). Again, make sure you have a TWRP backup on hand before attempting this because not alll phones have fully working custom firmwares. Also, not all custom firmwares are rooted by default but can be rooted.
THE FAR LESS DANGEROUS PART, ALL ARE OPTIONAL, ONLY DO WHAT YOU FEEL COMFORTABLE WITH DOING HERE
If you do not use google maps then you can choose not to use a phone with a google account. Just do not connect to a network until after you have gone through the initial setup screens. You also can optionally remove your google account. WARNING: MAKE A NOTE OF YOUR CONTACTS AND ANY IMPORTANT MESSAGES FIRST BECAUSE REMOVING YOUR GOOGLE ACCOUNT WILL DELETE THIS INFORMATION! If you need to use google's services then you could access most of them through a web browser. There are also some apps that will give you access to google's services in a sandboxed mode to reduce data collection outside of use of the app. The downside is lack of access to google playstore meaning you need to use an alternative (but there are many good alternatives out there, keep in mind most of them track you to some degree as well. I do not know if they still work but f0-droid might have a couple of programs that access playstore without an account you could try first) and most apps that require google services framework will not work without google play services. WARNING! THIS WILL NOT STOP GOOGLE FROM SPYING ON YOU, ONLY MAKE YOU HARDER TO IDENTIFY!
If you do not use an app that came preinstalled on your phone, disable it if possible. If you can not do so then check the app's permissions and disable all of the permissions that are not needed for the app to rn. For example, an SMS service has no need to monitor your GPS and a game does not need to make and monitor calls. Of course, many apps will refuse to operate if any permissions are disabled and Google Play Services will spam you with annoying complaints if you disable any of the permissions not needed for it to work which would require disabling notifications from it but will not stop it from displaying an a message saying permissions are disabled every time an app that requires it runs.
If you really want to go google free then disabling or removing Google Play Services is one option. Of course, the phone would have to either be rooted or be a device on which the manufacturer allows you to disable google play services. WARNING: MOST APPS THAT ARE LISTED AS REQUIRING GOOGLE SERVICES FRAMEWORK WILL NOT WORK WITHOUT GOOGLE PLAY SERVICES!
Make sure any app you use is not spyware to begin with and replace spyware apps you use with non spyware equivalents if possible. One good place to start is the f-droid online store although it does not have a decent replacement for everything. Finding out which apps are spyware and what are good non spyware replacements will require a lot of research.
Use a firewall to block internet access for spyware software you can not disable or can not find replacements for. Most firewalls work on a per app basis so you can pick and choose which apps access the internet. Many of them also can be adjusted to block specific internet connections. There are non root firewalls which run by acting as a local proxy and enforcing rules on internet traffic.
Alright with compromising a little in access to the world wide web? Well, you can use a more private browser. Do your research, just because a browser says it is private does not necessarily mean it is. Also, keep in mind that no web browser can guarantee complete anonymity without reducing what you have access to.
If you want to keep all of the browser functionality found in chrome and firefox then you can use firefox but have to follow a few extra steps first: Of course, your best bet is to follow a couple of guides on how to make firefox more private and stop tracking you but here is a run down of some basic stuff to do: First, install Firefox from anywhere but google playstore so you cna control future updates since Mozilla has been taking out features that allow users to control Firefox over time. Then type about:config in the address bar in firefox. Then do a search for telemetry, set all values to false. Do a search for safebrowsing, set all values to false. Do a search for experiments and set all values there to false. Then do a search for autoupdate and set the value of that to false. This will disable all tracking done by Mozilla and Google through Firefox (yes, you read that right, Mozilla puts Google stuff in Firefox) and since the next update might reenable some of these things without even letting you know there was an update and by not installing from playstore and by disabling autoupdate you ensure that you know when there is an update and can choose whether or not to install it and then make sure all of this stuff is disabled after the update. Note that about:config has far fewer settings you can change in firefox on android as opposed to windows or linux so there is no guarantee that you can stop all tracking by mozilla and google. Another thing you can do in firefox is install privacy related extensions.
Many web sites require use of javascript and other software that is considered to be a privacy threat. Furthermore, any web site using recapchta to filter out spam bots will be a pain in the arse since the more private your browser is the more likely recapchta will be to give you a hard time. This means to access certain web sites you would still need the default browser and have it fully unchanged. Of course, most web sites you need to sign up at in order to use fully (like forums and any site that allows you to post comments, for example) only give you a hard time when you sign up for them. You can temporarily install the official app for that web site to create an account for the web site and then try it in the browser of your choice or keep google chrome on hand for those sites that will not let you access them properly if you can not be easily identified.
You could also have an android device reserved for gaming that is separate from your phone if you like android games and do not mind carrying around two devices. There are some good android game systems with physical controls available online (I would recommend the GPD XD Plus since it has a clamshell design that protects the screen when it is not in use) and you can purchase a cheap bluetooth device for an older phone you are not using that holds it and has physical controls as well.
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