How do I get better at endgames?

I recently played a game where I lost my initiative after a useless bishop sac. (Warning* cringe game with lots of blunders)

How do I get better endgame knowledge, and overall gain a better understanding of strategy in the endgame?

You could read Dvoretsky's endgame manual

The whole purpose of endgame is to promote your pawns and win material enough to checkmate your opponent's king. You should exchange pawns on the side of the board where you have a pawn majority (say 3 pawns of yours to 2 pawns of your opponent on the queenside). Your king should actively participate in the endgame as it's worth about a minor piece. The more pieces you trade, the passed pawns become more powerful. Study endgame books (Dvoretsky's Endgame Manual, 100 Endgames You Must Know, Practical Endgames), mostly take a look at rook endgames as these are most common and hardest to play accurately.
Here are Reuben Fine's 15 endgame rules:

1. Doubled, isolated and blockaded pawns are weak, avoid them!
2. You should advance passed pawns as fast as possible.
3. If you have 1 or 2 pawns more, trade pieces and not pawns.
4. If you have 1 or 2 pawns less, trade pawns and not pieces.
5. If you have the advantage, don't leave all of the pawns on one side of the board.
6. If you are a pawn up, in 99% cases the game is a draw if all of the pawns are located on one side of the board.
7. The easiest endgames to win are clear pawn endgames.
8. The easiest endgames to draw are the ones with opposite coloured bishops.
9. The king is a strong piece; use it!
10. Don't place your pawns on squares of the same color as your bishop.
11. Bishops are stronger than knights in all positions except ones where the pawns are blockaded.
12. 2 bishops against a bishop and a knight are a real advantage.
13. Passed pawns should be blockaded by the king.
14. The placement of the rook on the next to last rank (7th for White/2nd for Black) is compensation for being a pawn down.
15. Rooks belong behind passed pawns.

@Dario19503 Thank you very much for the advice, I had heard of a few of the rules, but there are a few that I never had seen. I'll be sure to check out the books as well!

nice compilation

I have a bunch of studies on endgames, such as my Rook Endgames study.

Click on my profile and go to studies, then Rook Endgames.

@PurpleCherry

Try this...

https://chess-endgame-trainer.web.app/home

@Dario19503 :

I never heard the rule 2 "advance passed pawns as fast as possible". I am slightly surprised, because there are many endgames, where it is pivotal to delay - and prepare - the advance of the passed pawn! To highlight this I created a study with four examples:

Start with the basic endgames first. For example, K+P vs K. This helps you to evaluate more complex positions. Read an endgame book, this is the best thing to start with.
I experienced several times that I was a pawn up in a rook endgame and my 1600 opponent voluntarily traded rooks ASAP and directly transposed to a lost pawn endgame. This just shows that they know almost nothing about endgame theory.

In your particular case, you can play the position against Stockfish with both sides. Then you might learn the ideas from Stockfish. Of course a coach could be even more helpful.

And, maybe sometimes underestimated, if you improve your calculation skill, you also improve your endgame skill. Deep calculation is required in many endgames and you cannot make the right moves with principles only.

Read Capablanca's books on endgames, has great endgame explanation, I hope it must be helpful