Endgame Deterioriated

Can anyone tell me where did I go wrong in the endgame? Up till move 20 I was microscopically better, then later it all went downhill.

My plan during the game is to go after Black's isolated c-pawn. That didn't go too well.

In move 32, I sac a pawn to place my rook behind passed pawn and push. (This is a mistake too.)

Any other strategic mistakes? Thanks.

By move 20 your microscopic advantage is gone.
Inaccurate was 14 Bxa6. Better 14 Rc1 attacking the c6 pawn.
Error was 16 Qxd8, leaving him the d-file. Better 16 Qc2 intending 17 Rfd1.
Error was 17 Rfe1, leaving him the open d-file. You should play 17 Rfd1 contesting the file, as he cannot take your e-pawn because of his weak back rank.