I don't think she was dealt a bad hand. She was an opportunist who was stupid enough to take over as leader when everyone knew it was an impossible job. I can't stand Gove or Johnson but even they stepped away after Cameron left because they knew whoever took it was going down in history as the PM who messed it all up. I think she brought it all on herself.
Actually maybe you're right. She was certainly an opportunist but her biggest mistake in my view was to call a snap election and THEN not to bother campaigning, relying on "if you don't vote for us, you'll get that nasty Jeremy Corbyn". Well for all their faults, Labour DID run a campaign worthy of the name and made massive inroads into the Conservative majority. Then what? The Tories saw fit to get into bed with one side of the Northern Irish divide. That should always be an absolute no-no, yet they carried on purely out of self-interest.
These are problems that the Tory party and Theresa May created.