H...
The way I see my ideal multi-phone setup working, I see the following five measures to prevent the above five consequences:
1) All phones would have 2FA authentification app installed; hence 2FA will be ensured at all times
2) All phones will be esim based; this will ensure that in case of a lost phone, the SIM number can be immediately transferred to the backup phone
3) All phone will have "Google find your phone" installed; this will allow me to delete all data from any phone remotely, even after losing access
4) Currently most of my data is already cloud-based; my photos are backed-up in google photos; I think this would be covered
5) I think this is the only missing link right now. Ideally I would like to have an app, that allows me to sync the app setup on multiple devices, such that all apps I install on device 1 are automatically installed on device 2 (either auto sync in fixed intervall or on demand).
.....
1 -- 2FA isn't tied to any phone nor an Android matter, it's implemented by each online service that requires some kind of user login authentication. The issue being not very online service uses it. So it's not an app nor a service that can be installed, it's dependent on each online service to enable it.
3 -- There's a substantial number of people who oddly and perversely own Android devices but also detest and hate Google. They don't want to have services like Find My Device enabled because they simply do not want to Google to be able to track them on a real-time basis and the remote access features it provides is considered to be an invasive violation of their personal space.
5 -- Apple has a very comprehensive backup and restore that's integral to its platform, but Apple also maintains a tight control over its platform both from a hardware and a software aspect. Android is too diverse and multifaceted though so even things like the base file system can vary between one manufacturer to another. So creating a universal backup/restore utility is a tall order. Samsung's Smart Switch isn't as thorough as Apple's Time Machine but close, and it only applies to most but not all of Samsung's product line, and some cursory support for a limited number of non-Samsung devices. But outside of that, actually developing a universal Android backup/restore is going to require something along the lines of AI (Artificial Intelligence) that can scan and categorize incoming content (read a phone's internal storage), and then output that content into a potentially very different directory structure so that content gets copied into the appropriate folders and such, and all basically on-the-fly. Basically that's what happens in our heads when we have to manually transfer the content of an old phone to a new one. (i.e. music files on an old phone in a 'Music' folder get copied into the 'Audio' folder that's in the new phone.)
If you stick with the same manufacturer for all your phones whenever you upgrade to a newer one, you'll have more luck finding a manufacturer's auto-transfer utility. Otherwise, it's just a matter of waiting for the some software development to come along with a workable solution.
