Lapse.
Regular
My thunderclap 4x4 M is very slow for both inner and outer layers. I have lubed it already, but I have used slightly stronger magnets in the inner layer, making it even slower than ootb. Does spring compression help?
My thunderclap is also the exact same, for me i have to really aggressively turn and do about 30 solves before it starts to feel real good, and then the next day it goes back to being a terrible thing to turn. That bein said, i never set it up or cleaned it or did anything to the puzzle after i bought it. Maybe its due to the small size. Not really sure about spring compression for the thunderclap springs because i tried to compress it and it doesn't really go down much further, i only managed to compress mine by 1mm. You could cut the springs off or do a spring swap. OR maybe get a better 4x4 :/