DJjclay

My issues seem to have been resolved. Here's what I did:
In my router's settings, I set a new, unused IP in the DHCP Reservation settings.
In Unraid, changed the IPv4 static IP to the same IP I added in my router settings.
That's it. When I thought to do this, I wasn't even sure it would fix the issues, but I thought I'd just try anyways. l was only having issues with my server, not with anything else on my LAN, hence I was convinced it was my server that was the problem. It seems obvious now that I needed to assign the same static IP in my router as what had been set in Unraid, but I had no issues whatsoever for 8 months, so I was puzzled. Anyways, in hindsight, and considering my router is getting up there in age, it was clearly only barely been working for the last 8 months, and then it finally degraded to the point where the router wasn't able to figure things out on its own.

It's working perfectly now. Lesson learned.