Are you on one ui 6/6.1? Material colors being wrong is a Samsung bug and was fixed in 6.1.1

https://github.com/material-components/material-components-android/issues/3924

https://www.sammobile.com/news/one-ui-6-1-1-fixes-material-you-theming-issues-google-apps/

I thought you could not downgrade non-debuggable apps?

For android native apps (Java/kotlin) you can learn to mod the easy ones (that are not completely obfuscated) yourself. I do this with apktool_m.

Look into termux, proot, proot-distro and termux-x11

You have more limited performance in proot but it can run some basic programms

The good ones are mostly pc ports (dead cells, stardew vally)

I thought you saved power because the e-cores are more efficient for the same workload?

Keepass/KeepssXC/KeepassDX (password manager for desktop)

Syncthing to synchronize database between devices.