aadghjgh for example -app: covenant eyes blocks porn on iphone - is there a way to do it on graphene os? Regards!
nologo You can use family.adguard-dns.com (or another 'family'-focused DNS provider) either in Settings - Network and Internet - Private DNS, or in your VPN app if you use one.
freddo You could also use nextdns. You can add custom filters and will be able to monitor any requests that the device is making.
gristle-cause DNS filter with a block list is probably your best bet. NextDNS for cloud services, & RethinkDNS for local processing. There's more than a few 'child safe' blocklists already out there