i am happy to have a raspberry pi setup connected to a VLAN switch, internet is behind a modem (like bridged mode) connected with ethernet to one switchport while the raspi routes everything through one tagged physical GB switchport. the setup works fine with two raspi's and failover without tcp disconnections during an actual failover, only few seconds delay when that happens, so basically voip calls recover after seconds, streaming is not affected, while in a game a second off might be too much already, however as such hardware failures happen rarely, i am running only one of them anyway.

for firewall i am using shorewall, while for some special routing i also use unbound dns resolver (one can easily configure static results for any record) and haproxy with sni inspection for specific https routing for the rather specialized setup i have.

my wifi is done by an openwrt but i only use it for having separate wifis bridged to their own vlans.

thus this setup allows for multi-zone networks at home like a wifi for visitors with daily changing passwords and another fror chromecast or home automation, each with their own rules, hardware redundancy, special tweaking, everything that runs on gnu/linux is possible including pihole, wireguard, ddns solutions, traffic statistics, traffic shaping/QOS, traffic dumps or even SSL interception if you really want to import your own CA into your phone and see what data your phones apps (those that don't use certificate pinning) are transfering when calling home, and much more.

however regarding ddns it sometimes feels more safe and reliable to have a somehow reserved IP that would not change. some providers offer rather cheap tunnels for this purpose. i once had a free (ipv6) tunnel at hurricane electronic (besides another one for IPv4) but now i use VMs in data centers.

i do not see any ready product to be that flexible. however to me the best ready router system seems to be openwrt, you are not bound to a hardware vendor, get security updates longer than with any commercial product, can 1:1 copy your config to a new device even if the hardware changes and has the possibility to add packages with special features to it.

"openwrt" is IMHO the most flexible ready solution for longtime use. same as "pfsense" is also very worth looking at and has some similarities to openwrt while beeing different.