The Wii doesn't do 240p? or just in RetroArch? I could swear there are quite a few Virtual Console games on Wii that do 240, as well as bespoke emulators for most other consoles that can do it.
Might not be the best option if you want RetroArch as your interface to everything though.
This is being pushed by social media companies that don't want to be responsible for age verification