Another update.
I was still getting both scan results on both types of scans (the basic one and device specific one, as explained) with no consistency. I'll get one good result, one bad result, three good results, two bad, etc. So, I installed the new update (22.11) to see if that made any changes. It didn't. I did a complete uninstall (using the Avast uninstall/clear tool) and then reinstalled. Restarted a bunch of times in between all of this, and getting the same result.
Furthermore, I checked my Windows Firewall advanced settings, and the default setting where
Inbound connections that don't match a rule are blocked setting is still on, and the only enabled rule that has any of the ports Avast focuses on at
this link is one for File and Printer Sharing (SMB-In), but my Network Profile on Windows is set to Public and that rule is only enabled for Private (since setting it to Public hides your computer from others on the same network), so I'm assuming this should protect me against any issues that Avast is "concerned" about.
Even though the Network scanner wasn't finding issues with my router, I still did all the solutions Avast recommends in the above link, and did my due diligence and updated my Wifi and Router Admin passwords (to just use random alphanumeric characters for both).
I know that's a lot there, but I wanted to be thorough. If anyone has any insight into this, or if you currently have or have had the same issue, It'd be great to read. I feel like I did everything short of advanced port scanning or settings which I know next to nothing about and don't want to tamper with as a relative novice.