So it’s been a while since I’ve played so I might have some of these details wrong...
During the main campaign, I fully upgraded a few of the Witcher armors. Bear and cat for sure. Maybe wolf too.
You can get new armors to upgrade in Blood and Wine, and I think maybe get new upgrades to the original armors in Hearts or Stone. Don’t remember.
In Blood and Wine, the material cost to fully upgrade the various armors got so high that I said fuck it and just used cheats to put the materials in my inventory to craft them. I had already played the game for over 120 hours at that point and just didn’t have the time to go find enough money to buy the materials I needed, and this is coming from someone who had a fuckton of money left over from the base game. You burn through that shit fast when you need to buy all the super expensive stuff required to build the new armors from Blood and Wine.
I did do all the quests to find the armor schematics and upgrade schematics, though. Just couldn’t be bothered grinding to make the money to upgrade, as it probably would have taken another ten plus hours at least. I also burnt through most of my money on the upgrades in Hearts of Stone and completing the full base game armors.