I've (re-)upped the difficulty to Death March to keep the combat interesting. Fucked up difficulty curves are a CDPR hallmark, it seems.
I'm nearing the end now and the entire progression (difficulty, levels and loot) is just weird. Seeing how the numbers play out now I'm not sure the XP bug ever existed. It's probably just CDPR awkwardly capping your level so you don't outpace the main quest, instead of scaling enemy levels.
The way it is now you'd essentially have to make informed decisions to keep things even, as if you were playing a linear game. Main quest, side quests in immediate area (and only the ones you can actually do straight away), main quest, and so on.
The loot is jumbled too, specifically quest rewards, which don't seem to scale to your level. But then I also picked up a sword diagram with a level requirement of 47.
Or maybe I'm just not remembering right and/or able to place the relative worth of stuff, because I crafted Witcher gear so early and stuck to it. Which is strangely easy to get, considering it was supposed to be tied to difficult monster contracts...
All of this has the distinct whiff of a band-aid solution to it. Either that, or they didn't expect people to play an open world game like an open world game...