How would a player master these types of positions, with no annotated games to look at?
Play out a few lines vs yourself, try to maximise your piece's activity, defend/attack weak pawns, keep your king safe, and pressure enemy pawns. There are fewer pieces in endgames, so one perpetually passive piece hurts your position a lot. So as always if your king will remain safe prefer counter attacks to passive defense.
This shoudln't be too intensive, you just want a feel for the position. Now load it vs an engine and play it out a few times. After it kills you (or you draw) do a post-mortem type play where you play though from the beginning again this time leaving the evaluation window open.
After seriously considering your next move look at what it suggests. If it doesn't like your move then play it and find out why. If it likes your move but suggests an odd looking alternative play the odd alternative and find out why it also works. etc,
There is remarkably very little written about symetrical and equal endgame positions. When these positions appear in Grandmaster games, a draw is agreed and the game is over.
Take this position:
This game would just be declared a draw, and lower-rated players would have no way of studying the technique required to handle this position.
Here is another one:
It is actually rather common for me to lose these types of games against higher rated players, especially in blitz games. The higher rated will often just overpower you with aggressive moves, when the technique to hold the position might actually be very simple.
How would someone approach studying these types of positions, with no annotated games to look at? Playing them against a computer might be a bad idea, because computers are terrible at endgame technique.
Let me know your ideas, thanks.