4 bishops or four knighits.
Well that's a bit of a bummer.
But I feel at lower levels in guts would be stronger.

four knights white vs four bishops black. it said -0.62 (black has an advantage.)
four bishops white vs four knights black is a shocking +1.30 (winning for white.)
engines love those bishops.

four knights white vs normal black 0.00 (exactly equal)
four bishops white vs normal black +0.93 (white is winning)
Even against normal black board! Shocking! I guess that's the way the cookie crumbles.

keep in mind that against two average or below players that the knights could be a useful tool but objectively not as good.
This includes position. You have 2 for each colour.

four knights white vs four bishops black. it said -0.62 (black has an advantage.)
four bishops white vs four knights black is a shocking +1.30 (winning for white.)
engines love those bishops.
Yeah, which is why you can't really use them to evaluate a starting position like that. They can literally have a bonus for bishops coded into it. Just like when you get a late mid game positions the engine says are winning but there's no way to avoid various simple drawn endgames... they're even more unreliable in the starting position.
i just go on the stockfish on chess.com and put in the position and see what it says.