iCloud+ Private Relay feature disables Opendns DNS filtering

As part of the iCloud+ features is Private Relay. As a family owner, I share iCloud+ features (mainly storage) across my family including my children. To protect my children I use the OpenDNS service (now Cisco Umbrella) which allows me to set content filtering. However, when my children enable private relay, DNS requests no longer originate from my home router and instead are made via whatever DNS forwarder is on the Private Relay proxy. OpenDNS therefore do not recognise the request as mine and so my web filtering settings are ignored.

Is there anyway of disabling Private Relay for family members, or some kind of setting which allows web filtering services like OpenDNS to work? I know Screen Time has the "Limit Adult Websites" option - but i've found this to not be perfect and still allow sites i'd prefer it didn't. There is the option to add a custom list - but this is a reactive option, not a proactive one.