I’ve heard that some satellite TV splitters are not good for MoCA due to high port-to-port isolation. That Amphenol is supposed to be a good splitter. But if you aren’t using all 4 outputs, maybe get a 2-way for lower loss.

There’s no point buying a second router. If you are thinking it will offload some work from the first router, it won’t. An Ethernet switch may be all you need if you want to connect both devices to Ethernet.

I don’t own an Asus but I have recovered routers of other brands. It’s been years since I recovered a router so I haven’t kept up to date with the latest developments.

I assume that the recovery process you tried was the Asus Rescue Mode. If not, it’s documented here.

If that doesn’t work, many routers have a serial port that can be used to assist with the recovery. I found this post that lists the steps. It’s for a different Asus router but it will probably work on yours.

As you’ll see, it’s quite involved and requires you to buy a special type of serial cable (called a TTL-level cable). The cable is readily available on Amazon from a number of places and is not that expensive. It’s certainly cheaper than buying a new router. You have to open the router to connect the cable to the serial port inside. Then follow the process to start a TFTP upload of firmware.

Take a look, then decide if it’s something you are willing to try. You probably don’t have anything to lose other than a few $ for the serial cable.

Good luck.

The destination is showing a small amount of packet loss. It could simply be overloaded.

Since you have fibre Internet, do you know where the ONT is located? Is there any other wiring located near the ONT besides the Ethernet cable leading to the useless cupboard? If there's coax, then MoCA is a good alternative to Ethernet. You could put the router near the ONT and feed the MoCA network. Then install one or more Wi-Fi Access Points in the house to provide Wi-Fi. Dump the Powerline adapters.

Here is a prototypical MoCA setup (courtesy of gocoax.com for a fibre Internet setup). Popular MoCA brands in the US are Actiontec (Screenbeam), goCoax and Motorola.

traceroute on Linux uses UDP by default, while Windows tracert uses ICMP.

Try traceroute -I on Linux. You should get the same results as Windows.

Each switch port operates independently. Are you saying that all of your ports were running at 100 Mbps but switched to 1000 Mbps as soon as you replaced the one cable to the DVR? That would be very unusual.

Does another computer, like a laptop, work on your son's connection?

Are these logs from a device provided by Century Link, perhaps the modem itself? If so, the problem is clearly Century Link's. It even says that Wi-Fi/Ethernet is ok but the Internet connection is down.

You need to press Century Link to fix their problem. Show them this log.

I’m not 100% sure but it looks like a Leviton 47604-F6S. I think the 47611-C6 for Cat6 might fit. There’s also the 47603-C5 for Cat5e. See the full Leviton catalog. Please do your own research before buying anything.

Consider activating both Ethernet ports so that they connected to your router. Then your PC and TV can use them both for communicating with each other and with the Internet.

To accomplish this, you need to find where the in-wall Ethernet cables converge. There will usually be an enclosure. If you are lucky, the cables will be terminated either with RJ-45 plugs or punched down to female RJ-45 jacks. Either way, you want to connect them to your router. You can also connect them to an Ethernet switch, then connect the switch to your router.

If the router is located elsewhere, but is near an Ethernet wall jack, then you can put the Ethernet switch in the enclosure and connect it to all of the cables feeding the wall jacks. You would connect the router to its wall jacks. This will activate all of the other wall jacks.

LAG only works well when there is a sufficient diversity of traffic flows that can be distributed equitably across the child links. Since many LAG implementations hash only on MAC and/or IP addresses, the distribution can often be poor when there are only a few clients, as is often the case in a home network. This can possibly be finessed by careful assignment of IP addresses, but the point is LAG doesn't guarantee access to the entire aggregate throughput of the child links.

For this reason, I believe LAG is seldom worthwhile in a home network.