Seems like there is only one non-mame core available that supports these two systems. Atari800.
However, you can’t use it for both out of the box. Every time you want to change the system, you have to change the core option for that specific system.
Sure, you can save a core setting for each game… but what if you have full game collections? That will take time and will also make the cfg folder look like a mess with hundreds of individual cfgs just to tell the core what to run.
If there was a “save core options per directory” feature (like all other configs in RetroArch) this would be very simple and it would only require one cfg. But there isn’t.
So, how have you fixed this issue?