Otherwise Black plays ...c5 and frees his light-squared bishop. This is the only plan that fights for an advantage. The c5-square cannot be controlled by black pawns and therefore is a nice outpost for a white minor piece.
15.Bc5 seems natural but is strongly met with Nf4! winning a tempo over the queen. After 16.Qf3 then Black is fine after a5! intending a4 and Bc8.
The weak square on c5 makes the life difficult for the b7-bishop, since Black cannot push ...c5. Black could try to recycle it via c8, but this would disconnect the rooks and would allow White to gain control of the open file. Once again, the problem of a badly placed piece makes the whole position bad.
Unity Chess Club
Aleksandr Shimanov Magnus Carlsen Wch Blitz 2022 Black to move
The position looks very balanced and even the pawn structure is favorable for White, but naturally, there are many drawing chances due to the opposite-colored bishops. What do you play with Black here?
A great move, forcing white to play very precise no to end up worse. Black sacrifices the pawn since it is extremely dangerous for White to take it because of the f4-square!
And we reach an endgame where naturally Black is on top since the bishop is superior with pawns on both flanks. Moreover, the b2- and c3-pawns are still on dark squares and are easily targeted.