Interesting... I must have missed a purple orb then and made the game more difficult. I will do my best to explain the "minimal orb run"
- reach the island with the red orbs (activate checkpoint)
- go back to the purple orb that you inserted on the prior platform
- throw yourself of a cliff
- respawn on red orb island with purple orb in hand
- go to the next platform and insert the orb
- get the red orb
- bring the red orb to the third platform
- return to the second platform and retrieve the purple orb
- insert the purple orb into the third platform
- bring the red orb to the end
- win with only one purple and one red orb
- profit?
Yeah Unity does say that, but unfortunately you need to "upgrade" your Unity version thru the unity hub to support the other builds. You also need to switch platforms and make separate builds.
Honestly I don't blame you. I only know that since I am a linux main and there's only a windows builder by default. If I can give you a recommendation you should get the html5 builder. By far the best platform for jams.