I think Errant is around a 4? It's a little tricky because a lot of the time Errant follows relatively hard magic rules and has a fairly mundane world, but I'd put the power level higher than The Witcher or Harry Potter even though the magic tends to have clearer physical laws about what it can do because Rekki just picked up and chucked a car at a house-sized demon and that's pretty wild.
Like you can't magically fix your broken glasses with magic in Errant, and you can't turn a person into a frog (conservation of mass), stop time or teleport, but you can heal wounds, shoot magical death rays, leap twenty feet into the air or talk to ghosts.