The Petroff was something I knew well and used it OTB almost all the time.

Today, I have Stockfish 18 running and after 14...Qxc7 15.Bxd6 Qb6 16.c3 Rfc8 Black has compensation. However in the game, 15.Qxd6 is merited by SF with ?? Unfortunately, I demonstrate a lack of understanding and give the advantage back a few moves later with 19...Bd5?? I miss how the pin on the c file can be massively exploited with 19...Bh6! This causes mayhem as White tries to defend the threat of ...Nb3 Mate next move. If you are Stockfish you can defend with b3, b4, c3 or f4 but still evaluating at -2.5

35 years later I know I missed all that at the time.

My remaining moves reflect I am trying to keep everything calm. What a Miss.