hello @Pawnita
This happens to me a lot too and that's because your rating is higher than your opponent's rating. Since white starts with a 2.5 point advantage (according to stockfish depth 15), chess.com tries to make it a little more fair and give your lower-rated opponent the advantage instead. The idea is that you should be so good at your level that you can win against someone rated lower even with a disadvantage. Ik it's super annoying but you can rematch after a game if you want to play as white. To be honest tho, it doesn't rlly matter if you always get black because as long as your skill is equal to your rating you should still be winning.
Hopefully this is helpful
I've played lots of atomic and I'm always getting black. I think we can all agree that white has an advantage in atomic, so it would be fair if one game I'm playing as black and then white. I understand if I'm playing two or three times as black in a row, but I was black like ten times in a row. And the funny thing is that I was playing with someone as black, after that game was finished I clicked on "new game" and I played with the same person again... and guess what.. I was again black. Like why is that so..