How do you avoid getting overwhelmed by the high number of quests and unknown locations?

I started playing The Witcher 3 on a recommendation after enjoying RDR2 and BG3.

Act 3 of BG3 felt a bit overwhelming with its large number of quests, but it's nothing compared to stepping into Velen. The map feels massive, covered in "?" and notice boards... I tend to feel the need to complete every task, and there’s so much to do that I feel like I can’t finish anything. On top of that, I’m just a humble level 6 Geralt, but there are quests, gear, and "gear hunts" meant for level 30?! It’s like I’m stuck in a never-ending grind to level up and uncover mysteries.

I do like the "?" on the map since they help me feel less anxious about monsters or unexpected danger—I fear a little less for poor Geralt’s life—but wow, there are just so many of them...

How did you manage to enjoy the game more and feel less pressured?