Tactically, of course there's lichess endgame puzzles. But Josh Waitzkin says in the endgame you think more strategically than tactically, iirc.
Strategically, what's next?
Besides books (r/chess has a list), I'm looking for online courses or video lectures (preferably free, but even if not that's fine) that
have endgames that aren't covered in waitzkin's endgame series in chessmaster eg 2 rooks vs queen or knight vs knight.
have more examples of what the endgame course already has eg knight vs bishop, bishop and knight vs rook, rook vs rook, bishop vs same/opposite coloured bishop, etc.
Note: This has been asked on reddit but not for endgames specifically.
What I've found so far:
There's the Saint Louis Chess Club on youtube. Like I search 'endgame' there and then there a lot of videos, but it seems I'll get videos that don't necessarily follow some progression like in a course. In particular, they don't have a playlist for endgame.
P.L. Chess Endgame Course: There seems to be a lot of either endgame puzzles, w/c I could just do on lichess (but of course wouldn't necessarily gain understanding from the puzzles w/c is of course why I'm asking this question), or 'theoretical endings'. But some of the videos on this list I guess do kind of cover what I'm looking for.