Is there a mod to disable XP accumulation or at least slow it down?
Elex = Progression, loot and exploration.
Witcher 3 = Production values, music, story and atmosphere.
Pick your poison
This one looks decent. https://www.nexusmods.com/witcher3/mods/642/?
You can also activate level-scaling and see how well that works. (Should be somewhere in the options menu). I've never tried it myself because the option wasn't added until later.