Layout slow down - when Object Snap On and zoom in too close to dimension

Hi, I have been working in SU layout for more than 10 years.

Bugs are usually solvable until the 2021 version.

Now comes the problem of layout delay with 2 main commands: “object snap on” and zoom in too close to dimension.

I am working on a building development around halfway in the process, nothing complicated, I have checked there are no complicated objects, running roster image in viewport.

Now the layout would stop and “think” for a good 5-15 mins after I click on a dimension.
Other slowdowns including operation with Object Snap On, zoom in close to a dimension.

My question is what usually causes problems like this?