Just finished reading The Wrong Stuff, about the incredibly rickety Soviet space program which often worked purely by luck and coincidence.  For example again and again the Vostok descent module wouldn't separate from the instrument module, it was only when the heat of reentry of the out-of-control tumbling Vostok burned through the connecting link that the descent module was able to stabilise and not burn up in the atmosphere.

Eight years later they still hadn't got the two to separate, and it was still only the reeentry heat burning up the link that avoided the cosmonauts dying on reentry.

Korolev, the Russian equivalent of von Braun, estimated the N1, the Soviet equivalent of the Saturn, would require a minimum of four years static tests to get right.  They ran it with zero static tests, which resulted in all four built failing on launch.

The Soviet setup was so dodgy that when Kennedy proposed a joint program to Kruschev to avoid duplication of effort, Kruschev turned it down because he didn't want the Americans to see how duct-taped together everything was.

I've seen similar writeups of Soviet aircraft design, everything was kludged and bodged and hacked together with minimal testing, to the detriment of pilots and operators.

If this is indicative of other Soviet equipment then it's not surprising how poorly it's performing in Ukraine.