This has been discussed in this forum at length.
A majority (a large one) of users still want the Google stuff. You don’t sell Android phones in numbers without an Android with all the Google stuff.
You can get impact investors all you want … you don’t sell, so you don’t make your statement, so you’re finished.
And LineageOS … could end tomorrow (slight exaggeration). It is a voluntary community effort. And there’s no chain of responsibility if something in LineageOS doesn’t work.
Something doesn’t work, and the community can’t fix it, because the fault is in AOSP? Good luck with getting that fixed. The next major Android version will be out in a matter of months and Google will not care much.
You can’t run a business on that.