It's cool that you're interested in this idea. Well, for instance, the creators of Alwa's Awakening (NES-inspired indie game) asked the community for help (on Twitter in this case), and it is currently being ported to the actual NES hardware... -- https://eldenpixels.com/alwas-awakening-nes/
You might find it interesting that the GBA Jam 2021 has just started, a retro coding event which celebrates the 20th anniversary of Game Boy Advance: https://itch.io/jam/gbajam21
Here you can find a list of retrodevelopment and reverse-engineering Discords: https://old.reddit.com/r/retrogamedev/comments/e2l0zu/retrodevelopment_and_rever... Including one for PlayStation 1, and if you join the Emulation Development Discord you should also find links there to GameCube/Wii/Wii U/Xbox 360 emulation/development communities. The communities should help you get started with links to resources, and show you how to test your programs on original hardware or via emulation.
Check out this video as well, Making a Game for FIVE Different Consoles - Ludum Dare 46 [PS Vita, Nintendo DS, Wii, GameCube, and PSP]: https://old.reddit.com/r/retrogamedev/comments/i4zaj7/making_a_game_for_five_dif... Good luck!