*Remake something like the Game Genie that fixes the errors and supports GBC mode.
*Make a custom device with a Game Boy slot attachment or Game Genie slot attachment that fixes the bugs in the original Game Genie. So Game Genie>custom cart>Pokémon cart or custom cart>Game Genie>Pokémon cart however there may be troubles related to getting it all to fit, as when I tried it I can't have a Pokémon cart in an Xploder (another cheating device) in a Game Genie)
*Enter a Game Genie code in addition to the other codes to remove the white screen
*Try the Game Genie on Super Game Boy in case SGB mode works and fixes the white screen?
*Do https://glitchcity.info/wiki/Cart-swap_arbitrary_code_execution arbitrary code execution somewhere.
*Do a Glitch Dimension while it's all off screen to fix the white screen? Machop cry Coin Case is the classic one that works but Glitch Dimension Unown may need a little less memorisation of inputs once you get one. It may also still not fix the problem.
In extension, the physical Game Genie only allows for three codes. I wonder if there is an ideal way to have it support more? Thanks.
*Do a non-cart swap ACE code to fix the screen?
Edit: News! In Gold, if you open the Pokédex on the white screen, you can get a slightly playable version of the game once you close the menu again, where the people sprites/OAM objects are green, but it seems everything else is still white. I tried a Glitch Dimension with a Glitch Unown but it didn't work.
Edit 2: Yay! You can just run the in cart-swap ACE F3 16 0B 01 FF FF 0B 79 B0 20 FB 15 20 F5 3E 11 C3 00 01 (Can probably just cut off the first bit to get rid of the delay). I entered some codes and the Bicycle is now working as Fly once I make the wild glitch Unown codes for Gold/Silver I'll see if they work, but you've got to remember the last digits you enter in on the Game Genie menu as they're only visible when moving into the code line.