If you’re looking to increase your wired LAN speeds, it will probably be cheaper and easier to get an mGig-capable switch that is separate from the router. This will handle all of your LAN devices at up to 10 Gb/s, and you can uplink the switch to one of the ports on your router. For the most part, your router really only needs to support the speed of your Internet connection. Any local traffic between wired devices on the LAN will never traverse the router.

Ideally your link speed would be at least as high as the speed you’re paying your ISP for, if it’s not then you are theoretically not able to fully utilize the bandwidth you’re paying for.

The speed you’re paying your ISP for refers to the connection between the ISP and whatever their demaraction point is at your home, typically this would be their modem.

The link speed you’re seeing here appears to be a WiFi connection between your PC and your router.

Sometimes you have a modem and a router, but it is increasingly common for ISPs to issue modem/router combo units these days (i.e. where a single device both terminates the incoming connection, whether that be DSL, cable, fiber, etc., as well as provides Ethernet and WiFi connections for your devices).

In most cases, you are responsible for all networking beyond the modem/router (which would include the 400 Mb/s link speed you’re seeing here). If possible, it’s always preferable to use hardwired Ethernet since it’s performance and reliability is much better than WiFi.

Troubleshooting WiFi connections is a much deeper topic since there’s so much that goes into it, but in general, you want to make sure that both your devices and your router support the latest WiFi standard, you’re using a channel with the least amount of interference, and you have your router physically located such that it covers the maximum area.

Anything autopay is on a CC for me so it’s relatively simple. If it’s a legit bad charge, I just dispute it with my card issuer and let them handle it.

Based on what you’ve stated, it absolutely sounds like an AT&T problem.

If the problem continues, simply disconnect your router and connect a PC directly to the AT&T modem. If the problem continues, AT&T won’t be able to blame the problem on your equipment since it’s disconnected.

FWIW, my experience with AT&T fiber support has been abysmal. I had a similar issue and the tech they sent out straight up lied when he filled out his work order, saying the issue was my router even though he used his AT&T laptop connected directly to the modem and experienced the same problem. They tried to charge me $100 for a site visit because the problem was on my side. Took nearly 3 months of fighting with them to get that fixed.

It entirely depends on whether Xfinity has backup power for all of the devices upstream from you, how well those devices are maintained, and how much fuel they have.

In my experience, cell towers are generally pretty reliable and seem to have first priority. In an extended power outage the generators powering individual neighborhoods seem to run out of fuel after a few hours.