too bad more and more of android was moved into play services over time
You can still run Android without GMS core and Play services -- I do that, myself, on a Pixel 3a running Graphene. The trick is that you lose some nice functionality (which Android actually makes up for in some cases, ie: SMS OTP copy buttons), and the mapping experience is god-awful (mostly because the OSS mapping scene is hopelessly stuck in the 1990s GPS model)
e: here's an article from 2018 with some more examples:
https://arstechnica.com/gadgets/2018/07/googles-iron-grip-on...
Lack of media playback options shouldn't be able to stop you from using AOSP.