It's still built on Google's Android prohect and runs on Google hardware. Start learning Linux. The nice thing about Linux phones is they can run Linux desktop apps, which was a lifesaver for me when I used one as a daily driver. For example, by using Evolution and Nextcloud Desktop I was able to sync contacts, calendar and tasks between my Linux phone and Linux laptop.

How many mobile-first Linux apps are there? It's probably very bad compared to APKs. Maybe AI can help here

Not many, but they have the basics. Plus Waydroid gets must Android apps working on Linux phones if you feel you must have an Android app. There are also responsive apps that redraw according to the device or screen width. There are definitely more responsive apps on Linux phones. See the Maui Kit project (KDE) Signal and Telegram are responsive and work on Linux phones. Lollypop is a good responsive music app that works well on phone and desktop. You log into "Online Accounts" on your Linux phone, just like desktop, and install Evolution desktop onto your phone, and that gets all the contacts, calendar and tasks working and syncing. You don't ever have to open Evolution after it's set up. There are movie apps for all of those. That was the state of Linux phones running the Phosh Mobile OS (Debian) 3 years ago. They may have everything working without Evolution at this point.

Also, how many desktop apps does Android have for use with phone convergence functionality?