jordan No idea, the old Plus phones use scaling FYI so they're not pixel accurate, it's taking a 2K image but then downscaling it down to a 1080p panel like how Macs do when they're not on @2x resolution. If you're sensitive to that I'd recommend a regular 7 instead.
All I know is that my regular 7 with an earlier version of iOS 15 is very comfortable compared to my SE 2. It does have a P3 color display, but it doesn't seem to affect me — even though it still does display brighter reds than sRGB, it doesn't have the extremely oversaturated reds that my SE 2 has.
The only reason I don't use my 7 really is due to 60% battery health and a broken "loose" charging port, meaning I can't use it while it's charging and mine only lasts for 1 hour. But you can definitely find a 7 in way better condition than mine is, lol.
I've heard some people here talk about iPhone 7 suddenly becoming unusable with iOS 15.7 or 15.8, so look for one on an earlier version.
IIRC I remember iPhone screens starting to feel "weird" (way before I learned what temporal dithering was) when the iPhone 8 launched, I knew a friend with an iPhone 8 and even on its original version I thought the screen looked "weirdly smoothed out" or "overly glowing and shiny" to me. So iPhone 7 is probably the last "good" iPhone LCD, at least concerning how the software is choosing to render to it.