As for Brutes;
Pre-Halo, Brutes didn't seem particularly advanced.
Pre-apocalypse 1, Brute clothing and materials have zero actual elaboration. We know what weapons tech they had (Electrolasers), we know they were spacefaring enough to colonize moons, and we know they blew themselves up.
I wager that Brute attitudes towards clothing are sharply determined by social skein, with ones belonging to Rh'Tol likely being more adamantly opposed to non-utility equipment that kept them light, was breathable, and required very little care. Clothing among the Rh'Tol, due to the austere requirements of their homeworld and their relatively uncaring/undisciplined nature, is likely derided outside of strict necessity; Meaning that on Doisac, Rh'Tol were likely more typically raiders, preferring to pillage and burn instead of build and maintain. What little clothes they wear denotes the emphasis they place on clothes; Basic needs (Helmets, belts for equipment) and trophies/Rank signatures (Captain Banners, skulls, crownlike helmets).
Conversely, the Vheiloth have displayed a consistent desire for clothing, with all marks, ranks, and adherents to Vheiloth or similar Master-Pack philosophies extensively shown being clad head-to-toe in mass-produced clothing, primarily leather and hide with metal coverings. Vheiloths, by implication, are willing to stay static long enough and conserve enough material to produce war material, and by extension, they have a much broader field of armor and weapons development. Whereas one could confer that the Rh'Tols were nomads and raiders, Vheiloth are clearly more static settlement builders-the basic philosophy of their equipment indicates a culture of melting down and recycling equipment into workable purpose, with the extensive usage of leather indicating significantly more downtime and care to be had in how they approach everything. This also means that I figure the grand majority of Vheiloth clothing is not meant as a status icon; Most Vheiloth likely utilize a limited jerkin and pants, with the grade of care in the equipment and extensive usage of said leather determining social status, with care of armor determining such in a martial setting.
In other words; Rh'Tol's clothing choice or lack theorof indicates that they were nomadic raiders with a short-term survival mindset, and Vheiloth clothing choices indicates they were static scavengers with a long-term survival mindset. I wager they were, less than determined pre-Immolation, actually determined more by need and access post-Immolation. If they were around pre-Immolation, I'd posit that the Rh'Tol were the aggressors in whatever war caused the collapse, at least until national identities would've ceased to matter in the fallout.