So the best strategy would be to add to mGBA (or whatever somewhat accurate GBA emulator) something like "Dolphin GBP connexion mode" that is intended to run in background? Dolphin would interact with mGBA the same way a GameCube does with a GBP? I don't know how real hardware communicate but I guess that basically it's something like GameCube (Dolphin) sends orders and inputs, and then GBP (GBA emulator) send frames to GameCube (Dolphin)?
From France with love.
Laptop ROG : W10 / Ryzen 7 4800HS @2.9 GHz (4.2 GHz Turbo disabled unless necessary for better thermals) / 16 Go DDR4 / RTX 2060 MaxQ (6 Go GDDR6)
Laptop ROG : W10 / Ryzen 7 4800HS @2.9 GHz (4.2 GHz Turbo disabled unless necessary for better thermals) / 16 Go DDR4 / RTX 2060 MaxQ (6 Go GDDR6)