lilglasco

Options > Emulator > Save Type > Select Automatic and Flash 128K

You drag and drop Red Chapter's ROM File and that's it. Otherwise, go to File - Open and select it manually.
Don't forget to set the Save Type to Flash 128K. By default, VBA has it set to Flash 64K which doesn't work correctly for the pokémon games.

I never had an Apple device, so idk where do you find a Mac compatible version. Use Google.

Use VBA. Using a hardware-accurate emulator like mGBA to play hardware inaccurate ROM Hacks is just not a good idea.

Stop using mGBA to play ROM Hacks.
If you're on Mac and you're using OpenEmu, it's still mGBA.