A free mod for Witcher 3, by MioMilo.
The Better XP Curve mod makes it easier to experience the game's progression, as it changes the amount of XP needed to level up. You can enjoy exploration, contracts, and side quests without ruining your game experience.
The first thing you need to know is that this mod is outdated. It has not been updated since then, so there is a chance that it will be outdated when you install this.
I created this for my personal use a bit after the game was out, I did not updated it since then.