Yes 27...Rf6 looks strong - you can win the g1 Rook with a skewer
instead of 41...Ra8.
Note this mistake was played by your opponent the move after
he won the exchange (he relaxed, 1-0 in the mind but not on the board).
You should have held the c5 Knight outpost with a5 (stops b4).
That way your Knight would not have ended back on b8.
Funny to see it settle on c5 again.