You won this on one punished blunder, not on the opening you built.
The English gave you +2.0 out of the opening and it was still +2.1 at move 11, with a broad centre and your bishop holding Black's knight on f6 in place. Eight moves later the game was level, and it stayed level until jhonsnow23 gave you a piece.
8.Bg5 -- the right bishop move, two moves early
Sixteen seconds, and +2.0 became +0.9. The bishop belongs on g5; the engine plays it too, just not yet. Its line is O-O Bxc3 bxc3 O-O Bg5 h6 Bh4 d6 Bd3 Bg4, still +2.0.
The gap is one character. In the game the capture came as 8...Bxc3+, with check, because your king was on e1 and c3, d2 and e1 sit on one diagonal. In the engine's line it is Bxc3, no check, because the king has already gone to g1. That check is a free tempo.
It cost little in the end, since Black gave it back and you were at +2.1 three moves later. Worth naming anyway: you did this against Gugabud with 15.Qc2 and 17.Qxg5, the right square found before the position was ready for it.
11.Bd2 -- the pin comes off and the advantage halves
10...h6 attacked the bishop, so it had to move; where it went mattered. Twenty-one seconds, and +2.1 fell to +0.5.
Bh4 was the move and the only one. The bishop stays on the h4-d8 diagonal, and you can check that on the board: h4, g5, f6, e7, d8, with Black's knight on f6 and queen on e7 both standing on it. The knight cannot move. The engine plays Bh4 d6 Bd3 Bg4 h3 Bh5 Re1 Qd8 Rb1 g5 at +1.9, where Black has to spend Qd8 just to break the pin.
There was no menu. Be3 and Bf4 both come to +0.6, so every square other than h4 hands back the same pawn and a half. On d2 the bishop attacks nothing.
After 20...Rxd4 against Drotciv the question was what a piece was defending before you moved it. This is that question with a wider answer: a piece can be doing a job without defending anything. Name what it holds in place.
20.gxh3 -- the sacrifice on h3 was just a bishop
The game was level at -0.2 when jhonsnow23 played 19...Bxh3. You took, and it was +3.9.
Taking was the only move that held, so the work was in seeing it was safe rather than in choosing it. The engine's continuation is gxh3 Qxh3 Qd3 Qd7 Bg2 Rxe1+ Rxe1 Re8 Rxe8+ Qxe8 Bf4. Bg2 is the point: the bishop comes back to cover the king, both pairs of rooks leave the e-file, and Black's queen on h3 is one attacker with nothing behind it. A bishop for two pawns and a queen sortie.
This part of your game keeps holding up. Against Drotciv you found the only move three times running from a lost position. When the loose piece is theirs, you see it.
30.Be6 -- f7 was undefended for exactly one move
29...g4 left #15 on the board, mate in fifteen. Thirty-two seconds later it was +5.5: still winning, no longer forced.
Rxf7+ was the move: Rxf7+ Qxf7 Qxh6+ Kg8 Be6 Qxe6 dxe6 Rxd2 Qg6+ Kh8, and White is +9.7. It stood 3.9 clear of the next best, so this was not a choice between candidates. Read the fifth move of that line: Be6, your move, arriving two moves later with Black's queen dragged onto f7 where the bishop hits it.
The mechanism is a count. Before 30.Be6, f7 had two defenders, the king on g7 and the queen on h5 down the h5-g6-f7 diagonal, against your rook on e7 and queen on e3. Black's reply 30...Rf8 made it three, and the sacrifice never came back. Be6 also opened the fifth rank: with the bishop gone from f5, the queen on h5 sees d5.
Twice this game the square was right and the order was wrong. Ask for your checks and captures before your improving moves.
What to drill next
- The position before 30.Be6: play it from here. Pass condition is finding the rook sacrifice without a hint, then beating the engine from there three times running.
- Attacking f7 puzzles. That is the pattern you had and did not cash: a defender count on f7 that comes out in your favour, usually for one move only.
- The position before 11.Bd2: play it from here, with the theory page for this line for what the bishop is doing there. Pass condition is ten moves from that position without the eval falling under +1.5.
Before the natural move, look for the forcing one.