To add to this, the advice I've been given as a new/low rating chess player is to study endgames, if you must study something specific.
How to close a game where you’re up a rook or a queen (without stalemating).
How to close a game where you’re up one pawn, if it’s not a forced stalemate.
Two bishops is maybe something you want to learn. Theoretically knight + bishop as well. I play a lot of bullet chess and pretty much never see these though.
The rest you can really only learn with practice and pattern recognition, like how to move your pawns and how to use a minor piece to secure a win. Well, you can try to learn it algorithmically but I wouldn’t recommend it. After learning those I would move onto tactics, because those are generally how you gain a material or positional advantage that doesn’t rely on a very trivial mistake like leaving a piece uncovered.
Also, if memory servers me I've seen two grandmaster games only during this week, where this endgame could happen, but the players didn't want their opponents to show the technique. One of these games was yesterday: https://www.chessbomb.com/arena/2020-russian-championship-su...
But indeed, rook endgames are way much more important from a practical point of view.
Study mating.
Chess is not about how you start but how you end.