The Xiaomi Poco F5 Pro, its bootloader can be unlocked and it’s fairly powerful. I am sure a good rooting and modding community will come out of it.
However, the unlocking process can take a couple weeks which is not great, also MIUI by default sucks.
The Pixel line is always pretty good for custom roms and stuff
To be honest you can get Cave Story for free already since it’s open source and in many distro repos. Also I think the publishers kinda ripped off the original creator so the guy who actually put the work making this masterpiece isn’t getting anything