I'm watching Frieren right now and it's quite good when it's at its best.

That said, while the intro is catchy it has like 3 acts and is this really fast up-beat song, almost hyper-pop? When paired with the outro (a grand ballad that very frequently begets a jarring shift in tone at the episode's end, and beginning) it feels like the actual show only makes up like two thirds of the runtime.