I haven't quite figured out how to do 4K in OBS Studio (not Streamlab's version, the basic version), and I am playing on a 43" 4K LG HDR monitor, but this actual video is recorded in 1080p @ 60fps so it's all over the place.
I got a new 60fps webcam to see if that made a difference, and a new portable green screen - after looking at the "no greenscreen required" software versions I'd tried out previously, they're just not as nice as a real green screen.
I like how this turned out, I think I'll keep it.
You can hear me, but there's not game sound at all - my wireless headphones weren't turn on at that point. oops.