Did Epic fixed breaking bugs in UE 5.1?

Did Epic fixed in UE 5.1 physics, bones rotation and constraints? One of the physics bugs for example peoblem with waking, bones - randomly rotate for no reason, while in UE4 same rigs import just fine, constraints - simply unusable, unpredictable.

Lumen and Nanites are awesome, but with such breaking and random bugs - this engine is good for nothing except for pretty scenes, with no interactivity. A lot of companies (our company and those who we working with, locally and internationally) are still using UE4, because of sheer underdevelopment of UE5. Though, some clients demand latest version, so we have to explain them that we will not do this for those reasons… it generates a lot of pain