how do I beat isabel bot?
It seems that she's good in the endgame phase, so I'd suggest some offbeat yet not bad opening which could lead to an imbalanced game where you can try to get an edge before reaching the endgame with some tactical motifs.
The one I really struggled against was Isla (1700), took me a good amount of games to get through that one!
Not sure, that one is very strong.
You could try the Alekhine's Defense since it was AA who dethroned Capablanca in 1927. Or perhaps check some of the openings played by Alekhine back in that WCC match.
That's totally on the speculative side though, other than that not much I can add, this is a former world champion bot so it is incredibly tough.
Never heard of anyone!
You could try asking in the Chess.com Community club forums however, there are many strong people there who have beaten top player Bots.