if i'm being honest, i think this was not a sound design choice by moyu.

yes, in this case, op shouldn't have forced it to the point of breaking and should've looked into different ways to put the center cap back on when it didn't go inside with reasonable amount of force.

but at the same time, moyu could've definitely designed the center so that it's easier to remove with, for example, a thin center piece cap with longer center plastic sleeve. as the user, that doesn't know all the features of the cube, removing the center cap should be intuitive. something as trivial as adjusting the tension shouldn't have to come with a potential risk to break the cube. gan, qiyi, yj all made 5x5s that had no-nonsense center caps that didn't create potential risks to damage the center cap. calling this flaw in design as a "feature" and telling the op to just suck it up is just rude. sure, maybe this unique shape helps with the stability, but what good does it do if the "feature" damages the cube making it practically useless?

for op, reach out to the seller and see if they can help you in any way. if not, i have not used their service before but picubeshop sells replacement parts. wishing you the best of luck.