In a way, yes.
JustMarkov
It depends. If we only mention security, then there's (probably) nothing to worry about. However, if you look at it from the perspective of the FLOSS movement, Accrescent does not support any third-party repos, claiming that they are "breaking the Android security model", and also allows submitting closed-source apps to the repo.
I'm so bummed that Accrescent is now part of the built-in App Store on GrapheneOS and is gaining popularity because of it.
Among modern devices, only Google Pixels support re-locking on custom ROMs, IIRC.
EDIT: Looks like, modern OnePlus devices can be re-locked too.
EDIT 1: Same goes for SHIFT6mq.
GrapheneOS
Google Pixels are the only options with this one.
No-Ad Modded Spotify from Balatan
Have you tried Spotube? It is a no ads YouTube Music client, that fetches your library from Spotify.
I can't recommend you a specific device, but can suggest a Bootloader Unlock: Wall of Shame, which can help you choose a device, as you are planning to install a custom ROM, like Lineage. Best of luck with your device search!
While your post is just: it doesn't work on my computer, so Linux is bad for a normal user.
No, KDE connect has a very different purpose.
Jokes aside, I find that attitude not very healthy.
Calling a source-available license "not proprietary", this is what not very healthy.
"Source-first" or "fair code" are just a fancy ways to say "proprietary".
If the license doesn't meet the OSD and does not protect four freedoms, then it is not open-source.
Latest release candidate was released a few days ago.
FUTO keyboard is proprietary.
Have you tried Audile or Audire?