I don’t think MGCB supports WAVs above 48KHz 16-bit, but most of your players won’t notice a difference between 48 and 96 anyway. That’s why many game engines and most streaming services (Spotify, Disney+, etc.) top out at 48KHz.
Popular game systems from the past decade or two, including the Nintendo DS, 3DS, GameCube and Wii, all output at 32KHz maximum, and this didn’t seem to bother fans of games on those systems either. My point is, you can still make great-sounding audio even with the 48KHz limitation.