Hi and welcome to the S3D Forum.
Like the OP in this thread it may be helpful if you describe the problem(s) that you are having. By doing so you would arm the Team, and willing Forum Members, with the information needed for appropriate response.
As a User interested in having a smooth, slick route to producing superbly accurate and splendid looking Designs, I have not experienced any unexpected reduction in S3D’s performance at any time. However I have made myself aware of the limitations imposed by processing huge amounts of calculations at one time.
It seems that problems, like the OPs, are satisfactorily dealt with but the manner of doing so, i.e., ‘backroom’ investigation case by case, satisfies affected individuals but fails to present the outcome to the Forum. Perhaps this has contributed to the need for your post?
Problem resolution in private does not help to disseminate knowledge that would both diminish the need for a lot of questions and benefit the community.
Be aware of the, very welcome, rapid and continuous improvement of S3D. This means it is highly likely that new problems will arise. At present the Team are under pressure to ensure that the move to iPadOS proceeds efficiently, even so I am sure they will respond if you provide useful information.