Rather than a question, I will reiterate (from experience) some of the things you said in the brief overview of elementary rook endgames.
- Rook endgames are extremely common, and there's a reason for it: rooks are usually the last pieces to be developed, so they engage in battle relatively late, which is why they usually survive till the end.
- Rook endgames are very subtle, to the point where even super-GMs routinely mix them up, even when they have time to think. In many ways rook endgames are even more subtle than other types of endgames, though clear patterns exist that help a player navigate them well by knowing and respecting known theoretical positions. For this reason, it's important to know those basics and build on top of them.
- Rook endgames are usually the most drawish ones, even when there's a material imbalance (one side has a pawn or even two pawns extra) -- a well-known adage among chess players expressed many decades ago by prominent players. Adding other pieces to rooks (for both sides) tends to sharpen the position and make it more winable/losable -- so if you aim for a draw, often an "escape" to a rook endgame helps.
Endgame Questions