Because of the ongoing transition from ipv4 to ipv6 in the internet, ipv4 will be limited in routing capabilities on the ISP-side.
With today DS-Lite stacks given by the ISP, the NAT-routing mechanism has been shifted to the ISP-side and not more than a local ipv4 network without public IP's is offered.
Here it is described how to install OpenWRT to a Linksys WRT1200AC. Other routers should be similar . A few basic features like printserver, DoH and mDNS are listed here.