@retropieuser555 Thank you! I will look into that!

@Scionni Did you have any other knock on effects of doing this method? I followed your exact steps, which worked awesome (thank you!) for configuring the controller in dolphin, but now every time I load up my Retropie I get this message which won't go away until I login:
Pac-Man Screen Shot 5-5-2.png

I've already tried going into raspi-config and selecting to autoboot to my user pi but that doesn't seem to work either.

Modify the emulators.cfg file from /opt/retropie/configs/wii and add a new emulator entry for the distro's version of dolphin. You can then choose this version from the runcommand launch menu and make it the default for running Wii games.

@wolfyn-claw That won't work on a stadard RetroPie image or on Raspberry Pi OS, since it's a 32bit (armhf) version. Support for the beta 64 bit image of Raspberry Pi OS is still beta at the moment in RetroPie, so YMMV if you wish to install it (manually, since there's no image provided for it).
FWIW, there are a few topics here in the forums with Dolphin installations - you can take a look at how other users have installed it and what are their experience with it.