Question for you 10 Yard.
There is a build out there for RPI4 called CRTPI which is used with the minijack breakout cables for composite input.
There is also the RGBPI-OS that is meant to work with their proprietary cabling/output solutions to CRTS/arcade monitors. I believe this will also work with the VGA666 adapter, and then you just need to transcode the VGA to whatever your screen can use.
In my vertical Astro City (1p 4b layout, for only vertical games, mostly shooters), I have a JVC D-Series TV. Unfortunately, it's of a vintage that ONLY accepts composite(yellow) and S-video. S-video is superior as it breaks out luminance from color information so in the end I will need to get this all back to S-Video.
The thing about these builds, is that they have a bunch of cool ass tech in them to output native resolutions much like arcade15z/calamity's work as well as like the green-antz converter board. I don't know the magic that they use to set the resolution, all I know is there is zero latency that I can feel, and the games and front end look absolutely amazing, certainly MILES beyond what I was getting with hdmi to composite/s-video "converter" boxes - they are all the same and I know they are garbage so I want to use one of these builds.
But somehow, I want your frontend to work with these images just like they do now, and even if I have to launch into the main frontend and pick DKAFE from a list, that would be no problem.
So the question is - Are you familiar with ANY of these projects on the raspberry pi? I would like to use the pi4 8gb because I don't have any other use for it and its the sunk cost fallacy right.....So I'm trying to ask, if it's not too much of a bother, if I were to provide you links to these images/github/etc which might make a ton of sense to you as you are a gifted programmer, and I'm just an old fart who knows enough to be dangerous. Would you take a look and see if they would work? I know your RPI solution is an image to burn on an SD card but could it be made available as like, a separate "app" or something I could launch either from SSH or the frontend? That might be all thats required.
I know I just rambled forever about this and I do have a windows machine that may verywell end up being what I use in this machine but like I said I want to use the pi for SOMETHING. I could even donate to you if this is something that we could make happen, probably not enough to be worth your time, but I feel like merging these projects are a match made in heaven and they would get ALOT of use. There's a ton of guys using PI's right now living in a latency filled bubble that aren't even aware of the problem, but I am familiar enough with DK to know I want the fastest, smoothest most responsive machine/screen I can get!
https://github.com/stuckonretro/CRTPi-Project - there are links to the other versions this is the main page.
They used to maintain a reddit thread but some ---uvulas--- in the community were picking on them so they just erased themselves from the internet and this has been stuck in 2020 for 4 years now, but it works INCREDIBLY well.
If I could get the program as a separate app/img/.sh whateever it is - maybe I can install it onto this OS and then it would be done and I could share it on archive or something for the people that would want it.
Thanks for reading my wall of text. Your frontend has been living rent free in my brain since 11:47pm last night.