Tool for Playing Out Endgames in the Blitz Pool

[Feature Request]
I think it would be very cool and beneficial if lichess could add an endgame option when entering the blitz pool. The idea would be that when entering the blitz pool, you could select a "start from endgame" option, and lichess would select from a database of equal endgames to have you and your opponent play out.

With this tool, you could build out cool features such as
1) the introduction of an "endgame blitz rating" specific to playing out this game mode,
2) playing from endgames with an evaluation that benefits one color, but with draw odds for the defending side, and
3) once the blitz game is over, refer the players to annotations on how to play the endgame. (Computers are not always helpful in explaining endgames.)

The tool would be very useful for players like myself who want to learn endgames by actively thinking about them and playing them out. Please let me know if such a feature already exists, and if not, if you think it would be possible for lichess to make such a tool!

About 50% of games will end in an endgame. Why would we start from endgames?

I can think of a few reasons.
1) Often, when an endgame is reached in a blitz game, both players are low enough on the clock that they have to play on autopilot, since they don't have time to think about the position. Starting from an endgame gives them more time to think about this phase of the game (without having to play longer time controls).
2) A common reason people play blitz is to practice their openings or try out new openings. The endgame tool would be analogous to practice or try out new endgames.
3) There are many endgames that books recommend you play out with a partner. This requires that you have a chess buddy of a similar strength that is also interested in playing out the endgame with you. This tool would solve that need to find someone to play out important endgames with.
Overall, I think the tool is mostly for educational purposes. We learn a lot from trying out new things in blitz, but it's hard to improve your endgames from playing blitz since chess starts from the opening.

I hope I explained my motivation for wanting this kind of tool!

How are you going to practice your endgame skills in real games if you start games from the endgame? How are you going to simplify the middlegame? How will you reach the exact same positions you practised?

"Before the endgame, the Gods have placed the middle game." - Siegbert Tarrasch

#1 What's an equal endgame?

Not quite what you asked for but:

tailuge.github.io/chess-o-tron/html/blunder-bomb.html?p=P

starts with eval:0 endgame position and you have to stop the game when a blunder is played by either side. You can the click through to the lichess game the puzzle is taken from to see what stockfish regarded as the blunder move.

#5 Yeah good question. One definition could be any position within a 0.3 computer evaluation. Another could be a defined draw in a tablebase.

#6 That's an interesting tool! I didn't know about it, and I think a lot of the positions in here could be a starting point for this kind of tool. I'm worried about the some of the starting positions being a dead draw.

It'd be difficult to curate the starting positions that can be played out. Some endgame books that include puzzles have noted endgame positions that should be played out.

I have added this option to lichess app.
2500 interresting endgames pb from some book.
You can play only vs stockfish.