I think I would try a couple things.
I don't recall you saying this was a problem before. This can be very hard on the Zwave network to do this. There was an app published recently to help solve this issue. You might try this and see if it helps with that particular problem.
For your Device Stats, there are some things that are writing a LOT of stuff to the database. For example, do you really need to store 630 old events for your Sensor: Office Multi ? Or 3500 Ambient API events?
There are lots of these devices in your list that where you probably could/should greatly reduce the number of events stored (Ambient API, Ambient via WU, Outdoor Ambient Panel) as a couple examples. Go to the really heavy used device's Device Stetting page in that list, and crank the Events and States settings down. My weather app, I only keep 3 events. Basically that is the equivalent of yesterday, today, and tomorrow for the dozens of items stored in that driver. Personally, I only keep 1-2 of most events and states, there isn't really a need to keep hundreds or thousands of crap you won't ever look at again.
My other advice is that I personally suspect that Maker API has a memory leak. That is a very heavily utilized app in your list. Others have said this in the past too, but nobody ever seems to be able to catch this happening. I would try deactivating Maker API temporarily, and see if it helps. If it fixes the problem, I would work with support to have them pull logs from your hub and try to track down the bug.