One possibility is that you are getting some small power outages or fluctuations, which plays havoc with hubs, routers, modems, etc. So, putting all of that on a UPS has done wonders for my home automation over the years. On another note...
Some may hate this idea, but I've long used a "backdoor/hard reboot" on my HA hubs by putting them on a wifi plug. That way, if I need to remotely reboot them, I can do so by cutting power and then restarting them 30 seconds later. I don' t use wifi plugs for much of anything except these hub devices, of course (all else is z-wave) but for this purpose it works well. We had a vacation property that was 500 miles away in the past (we live there full time now) but this trick saved me a couple of times back then.
Now, the caveat is that I'm a long-time home automation enthusiast but very new HE user (although so far I love it). So, I have not actually tried this with the HE except once when I did so by accident as I fiddled with the Leviton app, and the HE hub rebooted fine. So, you may want others to chime in before trying this, if you need to reboot often. There is always a chance it might have ill effects, I suppose, although I know nothing about the memory/storage used by Hubitat on their devices. Hard reboots are eventually hard on SD cards, but I've never done it enough to cause a problem, myself. I started doing this wifi solution when I had a Homeseer Zee running at one property, and it came in handy more than once for that. In fact, the lack of reliability with those devices and HS in general is what caused me to abandon Homeseer. I had the same setup for my ISY-994 controllers, but never needed it as they are so ridiculously reliable (but have other shortcomings that caused me to sadly but finally abandon them after years of using that device, and move to the HE).
The first thing I would try, though, is to put your hub AND all internet connection devices (modem, router, switches, etc.) on a UPS. The surge protection alone is a big help, but we get frequent outages at our place (rural Maine) so this prevents many glitches and reboots. Anyway, just some thoughts on ways to possibly mitigate the root problem.
