That appears to be the default Android Contacts app so that user interface is what you'll have to get used to. it's inherent to the app so either become more flexible and get used to it, or opt to instead use a different, third-party Contacts app. You might want to try Simple Mobile Tool's 'Simple Contacts' app, it's free, no ads, and Open Source (no ties to any corporate oversight), and it has a lot more options to customize its user interface and functionality.
https://play.google.com/store/apps/...ery.discoveryplus.mobile&hl=en_US&gl=US&pli=1
Install the app, set it up accordingly to your liking, and then go into the Apps menu and if possible Disable the stock Contacts app. (There won't be an Uninstall button since its a pre-installed app, and don't be surprised if even the Disable button is greyed out. That's dependent on the manufacturer's whims.
There are several other Contacts app options to choose from though. Look in the Play Store page for each at the included screen captures for the one that appeals to you the most. It's not going to be easy to find a contacts app that has none of those boxes you dislike in an upper or lower menu bar.
The simplest option is to stop relying upon a separate Contacts app and just do what
@Madd63 suggested, tap on the Phone icon and then tap on Contacts in the bottom menu bar, that brings up a clean, no upper or lower buttons listing of your contacts.