You have my sympathies, jaded. It can seem like a crap shoot at times and there is a lot of luck involved. The problem is that blinds are usually fairly high compared to stacks and a couple of BB folds can easily take us from being in a position of parity to having only 1/3 the chips available. There are a few things we can do to get an edge.
Firstly when there only 3 players left think about how each of them will probably play HU - aggressive or passive? Use Sharkscope
or one of the others to check on their experience - have they played a ton of HU or are they new to it. Then make a plan to beat them; usually if they zig, you zag. Steal chips from a passive player and let an aggressive one hang themselves - ie wait to get a hand. This is hard if you are card dead and getting shortstacked, but if you have folded to their aggression for 4 hands an open shove with ATC can keep you breathing for a while. I'd recommend not leaving a stealing shove too late: if the stacks are 9K and 4.5K and blinds 500 then think about a steal the next SB. If you leave it too late (11K vs 2.5K) a lot of players are calling with anything - to steal the villain needs to worry about losing those chips.
If your villain is very aggressive you need to draw a line in the sand; show them you are not going to roll over easily, give them a tough decision.