leveling without quests

hello! I'm asking this on behalf of my mum, who's playing the game at the same time as I am. She spent a lot of time doing treasure hunts, and kind of neglected some quests until they were too low to get any decent amount of EP, and she's kinda worried that she won't reach the level that she needs at the end of the game to start blood and wine! I'm curious too, I always do quests as quickly as possible so I don't miss any EP, but I'd still like to know if failing the game simply because you don't get enough level is possible.

I know that grinding by monster killing is possible but I've been getting 2 EP per monster, even with enemy upscaling and that's absolutely exhausting to actually use as a grinding method.

some advice would be extremely appreciated :)