This is very much the way to go if you don't own any original game files. From there you can explore other mods. I also recommend the included Doom 64 Vr mod and Wolfenstein 3D.

If you just wanna play the original Doom or Doom II - just copy the Doom.wad or Doom2.wad to the WAD folder in questzDoom on your Quest. Best played with the vanilla weapons pack included in the launcher.

Have Fun guys! Cheers Bummser.