There was a wild video of a Russian group mocking a tank and then discovering it was a Russian T-90 and its reactive armour was literally a construction brick.

https://old.reddit.com/r/UkraineWarVideoReport/comments/1gt1...

They also had to chase their latest stealth prototype drone (S-70) over Ukraine with a pseudostealth fighter (Su-57 Felon, one of only about 30) to blow it up themselves. Almost certainly due to the drone being so faulty they tried to destroy it. They didn't even do that effectively, the large intact portions surviving and being collected for UA intelligence.

https://www.airandspaceforces.com/why-russia-shot-down-s-70-...

Russia couldn't manage to get naval superiority against Ukraine, a country with effectively no functional navy vessels.