Wayland (KMS/DRM) and custom resolutions

[Nikoh]

Hi guys and sorry for my bad english...
I want to configure my home PC to run old/retro and new games; i have 2 monitor, first standard LCD 60Hz (primary) and second one standard PAL crt TV.
I want to drive old/retro games on CRT and new game obviously on LCD but here the problems begin because i discovered  that on Xorg i can't have 2 monitor with 2 different vertical refresh rate, no way i think... (for reference: https://www.phoronix.com/scan.php?page=news_item&px=GNOME-Multi-Monitor-Vary-Hz).
Maybe i can do it disabling xinerama and forcing each monitor to have his xscreen like :0.0 and :0.1... but i don't know...

Then i switched to Wayland.
Now am trying to set custom resolution (240p) on Wayland but i discovered xrandr don't work on that, only way to set custom resolution under Wayland is KMS/DRM then passing a custom EDID as a kernel parameter on boot process (maybe also at runtime?)
Ok, no problem, is a better method IMHO because EDID is standard and cross platform/system; i do that, i can use one edid with several video mode for my crt pal TV like nes, snes, amiga etc.

The big problem is to generate EDID; it seems does not exist an EDID maker/generator....   only commercial products like extron etc.
I found "edid generator master" trough his modeline2edid command but is bugged... imho...
Here http://forum.arcadecontrols.com/index.php/topic,140215.0.html I have seen that your switchres can generate EDID... really?
Is it right?
Can i use it on my Ubuntu 20.04 environment?

I also read what Calamity says here http://forum.arcadecontrols.com/index.php/topic,160023.0.html: Now we should also consider HDMI at least, as it's the only way we can get RGB from with newer cards.
in what way? some cheap converter?

last but not the least, i tried GA and I couldn't get it started; i tried with and without my second crt monitor.... where am i wrong?

[Substring]

The "old" switchres can generate EDIDs. If you use my groovyarcade fork, you'll find them in /usr/lib/firmware/edid. As I still embed the "old switchres" until the new version has edid generation inside, you can use the switchres command line to build the edid yourself. It doesn't support "extended" format, so just a single custom resolution, nothing more.

Using wayland is a bad idea anyway.