I'm a 100% with you. I've been running OpenWRT since the WRT54G days. It's not perfect but it's the original embedded Linux distro. I know plenty of people run UniFi these days but personally, I'll stick with my OpenWRT flashed APs attached to an OPNsense router/firewall.

That said, to each their own. I'm happy to see a multitude of options out there. One of these days I might just go back and build myself Linux/nftables router like the old days when I ran ipchains on a 100MHz 486DX4 running Linux.

I'll definitely take a look at Attended Sysupgrade, this is my first of hearing about it. Thanks for that.