If we want to have the bigger picture we'll also need to read this about rethinkDns :
Is this a free service?
On-device firewall is free. The in-the-cloud Rethink DNS content-blocking resolver has both free (public beta) and paid tiers (private beta). Currently, pricing isn't implemented and so the private beta is essentially also free till then.
From faq : https://rethinkdns.com/faq Not here about arguing, people need to eat and live under a roof ofc, even in foss communities, but I think people need to know about it before installing & be dependant to its (for the moment free) features.
Because if at some point one of its features you use are going from from free to paid, & then you have no money for this (as too poor for it, or the will/ethic to pay, etc) while there are no free forks/alternatives for the service : you have a problem. Not everybody is as good users as us using iptables or wireguard, finding different alternative may be hard to understand for others. For example, as I'm not a good developper : I personnally feel dependant to a lot of foss apps & choices they make. If the matter here is related to privacy, I think it's important to know that you may pay at some point for it.