Had no idea there was crafting, my highest is a 41
It's tied to one of the DLCs iirc, the chtuluh one that adds a bunch of horror/tentacle themed classes. It's a very lategame option that kinda breaks the game, because as long as you have money, you can craft near perfect items and doing that in a few spots(weapon and gloves were the most important for melee chars, forgot about casters) you'd get a massive power spike. It's also technically missable cause you have to do... something I forgot what but it's a quest iirc with multiple outcomes, one is the crafting, the other is unlocking a vendor with good gear, but the vendor will rarely have items as good as the crafted stuff(although in theory the vendor can have BETTER items, cause they roll with more affixes).
That said I also vaguely remember that unless you play on Insane you won't have much money to play with it, and also the difficulty curve being way different makes the merchant potentially better on normal/nightmare. Insane plays very differently because you fight so many elite monsters that you get way more loot, so while the difficulty is higher, the gear is also a lot more plentiful which leads to chars being stronger, it's a bit unintuitive but I remember nightmare actually being as challenging as insane, just in a different way cause you could be really starved for good gear.
Btw I'd heavily consider looking up class unlocks on the wiki(or potentially using the mod that unlocks them all directly), the base classes are kinda meh imo as they're the more basic stuff but some of the unlocked ones have the best class design in pretty much any game I played. Paradox Mage is one of the coolest thing for example(Temporal Warden to a lesser extent). Oozemancer was cool as fuck too although the unlock was one of the more annoying questline. Many of the DLC classes are also awesome so buying them was very worth it, they add a ton of cool playstyles and some new dungeons(the orc one adds an entire different shorter campaign, although that campaign is a bit ass and the last boss can go fuck itself, if you don't get lucky with certain gear drops you just kinda can't beat him and there's just not many places to overgrind unlike the main campaign).