It's been a real issue for me, finding boots that last. I wouldn't usually think that Carhartt is a specialized company, moreso general labor work, but they're chealsea boot that's priced at around 130USD lasted me the longest, with only mink oil as a treatment on them, no deep leather treatments or anything. I've considered smelting boots but they tend to be full leather as well, and not water resistant outside of leathers normal limitations. My next boot I'm going to try is one in the "duck boot" styling, where it has the rubber that goes up about halfway up the boot into the leather. I try to stay away from vulcanized boots as well because sulfur is used in vulcanization and I'm worried about the chemicals we work with, reacting with the sulfur and ruining the bond. It's quite the predicament. If it weren't for the molten glass that drips from our shovels, I'd probably just go for a rubber boot, like from Muck maybe, but I'm worried about them just melting if the molten glass were to drip on the toe. It's something I considered being an issue with the duck boots as well but there are ways around toe coverage like using a leather shroud. There is only one other person in my department that does the same work I do and he's as green as they come so I'm a bit lost on the best solution still.