Starting new thread, as old thread has been locked. New "Omega" v21 release has been in the repo for about a week. 21.0 release notes from kodi team are here.
With this new release kodi caught up with ffmpeg 6, and that means InputStreamAdaptive addon is packaged again and working for all your streaming needs. Also, in the old thread @Solarmass asks
How can I get these emulators? Game emulator addons are not available for Kodi (Linux).
I'm guessing @Solarmass talks about libretro cores adapted to kodi with project Retroplayer. The Retroplayer has been part of kodi since v.19 but the cores (emulators) it integrates, aren't part of source tree and not included with the package. But it gets better...
To use Retroplayer cores, enable 3rd party repository. From there cores and gamepad profiles are available as kodi addons. Having installed your preferred selection of addons from the repository, you can browse you rom folder and emulate roms with kodi. It is that simple. Works best if you have a gamepad.