You can do something similar on STM32 parts that have an LCD controller, which can be abused to drive a VGA DAC or a DVI encoder chip. The LCD controller at least is fully documented, but many of their parts pair that with a small GPU, which would be an advantage over the GPU-less RP2040... if there were any public documentation at all for the GPU :(
I used "composite" (actually monochrome) video output software someone wrote on the RP2040 for an optional feature on the PhobGCC custom gamecube controller motherboard to allow easy calibration, configuration, and high-frequency input recording and graphing.
Pictures of the output here: https://github.com/PhobGCC/PhobGCC-doc/blob/main/For_Users/P...
I wrote a couple of articles on how to do bit banged VGA on the RP2040 from scratch: https://gregchadwick.co.uk/blog/playing-with-the-pico-pt5/ and https://gregchadwick.co.uk/blog/playing-with-the-pico-pt6/ plus an intro to PIO https://gregchadwick.co.uk/blog/playing-with-the-pico-pt4/