might be off topic but don't you think it's weird that it was just one sun follower wonder if that's just p'nk black just being lazy, other sun follower like jimmy and those cats would be hard or maybe pb is hiding it in part 2

Way I see it:

Sun followers are people who injected or ingested the pink sand you see around the various maps.

White Complex injected people with the pink stuff in UComplex, which is where the sun followers come from.

Eventually, White Complex became able to remotely channel the sun followers' power, allowing them to make the facility in downcorridors. This is why James is desperate to stop you in whitecorridors - he knows that you'll channel power from him if you're allowed to enter the bunker.

At some point, things went bad and James (and maybe Pandora) went on a rampage. Everyone in White Complex was sent to their own instance of otherside. They might still be there, for all we know.

I think Jimmy could be a person in the white complex and reminds me of the ratman from the portal series i think

It can be said that Sunfollowers differ from each other in terms of strength. Someone like Inno (and possibly Pandora) can influence the space and change it to their liking. The vast majority do not have such powers, but they can serve more powerful Sunfollowers. I think James attacks the player in White Corridors precisely on Pandora's orders, because after losing, we hear Her voice, plus the entire section with the pink room in the Ucomplex talks about their connection.