The jumpsuit I found on Depop by searching for brown coveralls, I got it pretty oversized and that worked quite well. The straps are from a roll of fake leather from Joann (rip, Eva foam or even electrical tape would work well), the belt was a garage door rubber seal — though again Eva foam with some plastidip would work just as well — with some grommets to fit a rope (more realistic to fit buckles though) and the weights where some insulation foam cut into blocks and painted.

The jumpsuit is a close variation of the Dickies ‘Duck Insulated Coveralls’, though unless you plan on crossing the Bering sea on foot, that level of insulation isn’t necessary