It's worth it to build one. I know exactly what you mean on the 8520!
8520 are much easier to fly in a small space, my yard is really pushing it for a 2s brushless build, brushed fits much more easily.
I still fly the whoop often, they're just so fun!
The motor above was $2 in the 20 for $40 deal a while ago, so it's not too bad. Not like killing a $15 1106 or something, though it still stings a bit and reduces the supply of spares, came buy them anymore so it'll be awkward eventually.
One of the other motors has as been shaft too, guess it's time for motor maintenance.