Advice on Firmware and Config for AC3100

I bought and installed this router a few months ago and saw significant improvements in my overall networking functionality in the house. I've had some problems, too, though, and I'm hoping to get some guidance on what firmware would suit me best and a config to go with it.

I have a couple of Linux servers that are hardwired to the network, a couple of smart TVs that are hardwired as well, four iPads (current gen stuff), five iPhones, and Mac latop (WiFi) and a Mac desktop (hardwired). I...

Advice on Firmware and Config for AC3100