AmberELEC VS EmuELEC

If that doesn't work, you could try manually flashing an older version of Amberelec

351elec is now amberelec, and yes, it can run ports. Actually, I think it's better than ArkOS now, much more intuitive, so I recommend you that one.

It also sounds like you might be better served with Amberelec: https://amberelec.org/

I was in your place few months ago and I installed Amberelec. It's much better now, in my opinion.

Might seem kinda too obvious but are you sure you have the correct img for the correct device? Did you download from "new installations" or "upgrade" or "assets"? https://github.com/AmberELEC/AmberELEC/releases/tag/20230203

The Retrorun and Retroarch Yabasanshiro cores were removed on Mar 12, 2022 because performance with them is much worse than Yabasanshiro Stand Alone.

Considering Chocolate and LZDoom, both can work but what you would want is LZDoom for .pk3 files. There should be a guide here.

Ships with EmuELEC 4.3. Should I be upgrading to the latest version (currently 4.6) or leave it at 4.3?There seems to be a lot of bug fixes and stability improvements in the 4.6 update but I'm not sure if they would be a benefit to the "if it ain't broke don't fix it" 4.3.

Here is the direct link to the correct EmuELEC 4.3 version for the Arcade Box: https://github.com/EmuELEC/EmuELEC/releases/download/v4.3/EmuELEC-Amlogic-ng.aarch64-4.3-Generic.img.gz

As far as I know most of those boxes are just using Amlogic processors. You could try installing an emu distro such as EmuELEC on a new MicroSD card and seeing if it boots.

It’s for certain Pi alternatives and Android TV devices: https://github.com/EmuELEC/EmuELEC