Bishop vs. Knight? which is more valuable??

The bishop is worth about 3.25 pawns and a knight about 3 pawns.
Of course it depends on the position: in some positions a knight is stronger than a bishop, stronger than a rook and stronger than a queen.
That does not change that in general a bishop is stronger than a knight.

mid game i would say equal, depends on the game who will be more useful, late game, i don't remember got to end game with 2 bishops, but in the endgame ,(or mid game ) one knight can have the power of fork , super satisfying if you kill his queen or rook :3 ba dum tss

I'm reliably informed that careful analysis shows that the Bishop is stronger at all stages of the game. However Bishops can get locked out of the game. So I think the answer is that Bishops are more valuable, but you should take care to keep your Bishops in play while trying to trap your opponents Bishops so that they become ineffective.

Case by case
A Bishop has longer range which can go further and faster than a knight. Pass through between pawns if it is a good bishop.
A knight can leap other pieces, useful to fork attack, especially, attack the king and other pieces to eliminate major pieces like A Queen and a Rook.