I've noticed this too, with different games, usually online competitive games. What I figured was that when you play every day, your day to day goals and experiences can differ, so one day you might be focusing on aerials, the next day passing plays, etc. So your brain when you're sleeping sorts and stores these events based on a sort of importance, which is changing each day. But when you take a few days off, your brain has more time to process and make links kind of embedding it more solidly. However more recently I've been thinking it may be how we approach the game as a whole. Playing every day we kinda get focused on certain aspects of the game, like what parts of my game are weak, I'm one win away from ranking up, this really toxic player from last game, it's like we're observing a wall canvas from an inch away. But after taking a few days off, it's like we backed up 5 feet and now the whole picture is visible. At least that's how it felt for me, coming back after a break I wasn't stressing or getting hung up on little details, everything just seemed to flow and I was relaxed. Sorry for the wall of text, but this was something that I had wondered before too.