Virtual 4k Monitor For Streaming

I have a Sunshine / Moonlight streaming setup, my host monitor is 1440p, and I’d like to stream to 4k. I think the best way to do this would be to create a 4k virtual monitor for Sunshine that Moonlight can render.

I’m having trouble finding full information about a good way to do this, I’ve seen some info about kms, as well as an nvidia virtual monitor solution. But without specific setup instructions. As well as some older X11 solutions Ive ignored.

So, just wondering if there is a best / documented way to do this, or any other info / opinions. Thanks!