As a person with a not-very-powerful computer that attends a lot of vrchat events, I get desynced all the time. Only started happening since the networked IK update, and I think I know why. In spite of having every avatar blocked, friends included, I still get a ton of IK packets because the grey "blocked" robot still has IK.
I tried an experiment yesterday, joining on an instance filled with my friends. Despite having all avatars blocked, all nameplates off, and booting through oculus instead of steam to have the absolute minimum strain on my computer, I still desynced instantly on joining the instance.
But I tried another thing, mass-blocking 25 people at random in the instance so they no longer even had the grey robot. Lo and behold, no desync. I could even show a bunch of people's avatars with no problems.
The grey robot really doesn't need IK. It has no legs or limbs, most people wouldn't even notice if it didn't.