Hilfe mit meiner Monstera

Dude, Moss pole.
I mean idk what else is going on because people here will go on and on about drainage, light, over-watering, soil mixture, how long has it been in that pot etc.

But you said you wanted something you could buy to keep it upright, and that’d be a moss pole.

look it up on youtube, get your soil, and your amendments (perlite, bark), your desired pot, your gardeners tape, and set aside a nice evening or early morning.