What is this outfit called and where can I get (preferably a masc-coded) one?

That look could be matched/masced with unbleached cotton drill vest and pants. You could get a similar effect finding a pair of painter's pants and a matching or complementary vest.

Roundhouse Denim makes good quality jeans and sells factory seconds/irregulars for extremely cheap. You could try these painter's pants and look for a vest. Just about any vest in a color you like would work well too just make sure to get one without a buckle across the back or it will give ren faire (unless that's what you want!).

https://www.round-house.com/products/irregular-1101-round-house-american-made-white-painter-pant-dungaree-jean-second-no-returns-made-in-usa-chap-style-double-knees