So, I’m searching the best console to run 240p games thru RetroArch on a CRT (14" feels the best size for this): I’ve read the most mature homebrew console for this are Wii and PS2. PS2 is less powerfull but it has native 240p output and can run PSX native. Wii doesn’t have native 240p but ppl claim 480i/480p is sharp enough and the difference is minimal, also it’s more powerfull and can run more platforms. I would exclude more expansive options like FPGA or an ad-hoc raspberry.
It looks like one of the more recent versions of PSBBN Definitive Edition added partial support for third-party adapters. I haven’t kept up with the project lately and my setup is a bit outdated.