Painful "Philidor Position" Loss in my Longest Game Ever

In the 3rd round of the Slow Chess League Championship 2017 tournament, I suffered a heartbreaking loss in the longest chess battle I've ever had that exceeded 4 hours and 100 moves. What was particularly afflicting is that I knew it was supposed to be a theoretically drawn Philidor position, but having studied it too long ago, I made the same mistakes over and over and eventually gave in.

Yes, I know it sounds weird (if you haven't noticed, it is my nickname!) but I don't know my Philidor position. I had studied it in depth maybe 8-9 years ago but I remembered close to nothing when faced with it in an actual game, and whatever I remembered, I remembered wrong! But also, hats off to my opponent who kept creating problem after problem for black to falter. His perseverance paid off. Here's the game, fully annotated with the help of Komodo.

Take aways:

Immediately after resigning I thought I had played a decent game but had lost due to lack of technical endgame knowledge. But analysis makes it clear that my calculation was sloppy in the important decisons I took before we entered the technical phase, such as playing 23...e5?! which is forcing and should have been calculated thoroughly, 30...Rb1? which was very casual, and 34...b5? which misses the single most important tactical point in the position.

Obviously, one should know their basics. Know your basics. Know your basics. I'm on my way to learn them and I'll get there. But still, I could have easily figured out over the board that 81...Rg1+? just suits white's purpose. I realized that immediately after white played 82.Kf6! What is really strange is that I commited almost exactly the same mistake  a second time with 92...Rg2+?? I'm not sure what to make of this. I simply failed to let go of the fixed recollection I had of Philidor position: check the king from behind. But no move should be made in such a mechanical, impulsive manner. There is also a serious element of panic caused by extreme time pressure, but even if I had spent mere 5 seconds and pondered on what my opponent could play after my candidate move, I would have seen that it's not the right move to make.

So perhaps even more basic than basic endgame knowledge is mindfulness, attention, and making no exceptions to calculating responses from your opponent. That's what I'll try to take away from this game.