Ok, that helps.
There has been a known issue with zwave devices for a couple of months where if you have too many edge drivers, the hub keeps rebooting itself or recycling and you can get a lot of lag. I don’t know a lot more details than that, but if I recall, the only solution is to remove some of the edge Drivers That you aren’t using and see if that helps.
Here’s the community FAQ, with lots of details on edge drivers:
FAQ: I have no idea what Edge is. Is that a new developer tool? (2022)
This is also probably a good time to start getting familiar with the new community-created replacement for the IDE:
SmartThings API Browser+ ... Now Available to All
As for the specific method for finding out how many edge Drivers you have, I’ll leave that to other people to discuss.
Tagging @jkp
If you don’t think it has to do with the number of edge drivers you have, then the next step would be to run a zwave repair and see what error messages you get. But don’t try that until you’ve confirmed that you have a dozen or fewer edge drivers because the repair itself can get hung up otherwise.