Playing PLO when people are maniacs

Thats like complaining about fish that doesnt respect your raises and call. You should always prefer people that play too many hands instead of tight nits. tighten up your game and get it in as a dominating favorite when maniacs start gambling every hand.

Every strategy has it's weaknesses, that you can exploit. If opponent is too aggressive, you can exploit that in 2 main ways:

1: slowplay strong hands
2: play strong draws /vulnerable hands aggressively

The worst strategy versus maniac is to call with draws/medium strength hands and raise nuts. Easy for him to play against you.

First thing is to tighten up preflop. Second thing is based on the opponent(s). There are many different kind of maniacs. Is there only one in the table, or more?

If you indeed are in a table where 2-3 players are 3betting/4betting every hand and all flops are multiway, while people are just shoving hands postflop, all you can do is to wait for a good hand and enjoy the variance. But when you get it and stack 2-3 people, it makes the waiting worth it.