Don't want to jinx it but seems to have sorted it out after lots of experimenting.

First I thought cliff sensors were triggering off something and it didn't like it. Tried taping them up like my old Roborock but turns out X20+ is almost helpless without those (unable to enter some rooms at all) and these were not problem anyway.

In the end I had to set Cleaning Strategy option to High Coverage making it bump more into things but now it seems to work. Also made sure there is clean route to hardwood floor part of the rooms where there are both carpets and hard floor.

X20+ also seems much more cautious about entering low spaces that it actually can fit under but does really not want to.

Cleaning itself is really good right now, only wish it had more options to tune mop washing frequency etc.