Home Networking

I currently have a NETGEAR Nighthawk Cable Modem WiFi Router Combo (C7800) that I purchased 4+ years ago with two WiFi extenders and 1.2Gbps Xfinity. I'm noticing every once in a while the connection will be fine but have no internet connectivity and I have to reboot it 2-3 times to get it up and going again. This kind of feels like the last straw as I've been running into signal issues as I am adding more smart devices, so I'm considering finding a good replacement over black Friday.

I have a 2k sq ft home with a basement and I have various devices/cameras/sensors throughout the house, outside and in the basement which I've needed two WiFi extenders to reach everything appropriately. Basement I ran ethernet to, but I don't really want to run any more throughout the house. Router is currently in the front side of the house where my office is - so signal on the back side of the house and basement was too poor for the cameras to run reliably. I have a desktop in my office that is wired, but otherwise there are many devices / smart switches / etc. throughout the house which are all on the WiFi which I'm trying to get better coverage for.

I've been looking around at past threads and I think I'm kind of gravitating toward the TP Link Deco AX5400 with one in my office, one in the basement, and one toward the back side of the house. Price is not as much of my concern as is value and performance - I want what will work best for my situation without going too far overboard. So would this fit well for what I need?

Then my question is how important is a replacement modem? Should I just go with an Arris modem like this? Would I be okay using my existing 2-in-1 in bridge mode or is there a better alternative?