I myself run my routers with open-source aftermarket firmware, host encrypted DNS server locally with blocklists and don't share WiFi access to the guests (or) if required do so via a VPN; But all these requires some level of technical expertise and is out of reach to those who don't have it hence the need-gap.
I was told NextDNS offers some form of simple WiFi sharing, I haven't tried it myself but I guess such SW based solution to provide network security to those without technical expertise should be a good start.