To be honest i'd spend a bit more and get a setup that's much more future proofed.
I'd get a
UniFi Security Gateway (£105) for your router / firewall. People are running gigabit connections on this perfectly fine.
Add a
Ubiquiti UniFi PoE Switch (£108) for your wired devices, this will also power your access points over Ethernet.
You can then add a couple of
Ubiquiti UniFi AC Access Points (£60+) where required, maybe one at each side of the house? (depending on size) for great coverage.
You can run the
Ubiquiti UniFi Controller (Free to £75 depending on what you use) on your own hardware to manage the above hardware, however buying their cloud key would keep it all very simple.
Sure this would cost a bit more than a new high end router, but when you think you can pay £300+ for a good Asus router these days, you might as well buy some kit which is both future proofed and expandable as your requirements change.
Like you I've had various Linksys / Asus routers over the last 10+ years with custom firmware and always outgrown them as internet speeds have increased.
I'm actually using pfSense for my router / firewall in a Virtual Machine on my home server, however both that and the UniFi Security Gateway are great solutions.
You'll never go back to consumer grade routers once having something better.