Not to sure about TC but with Marcell's original work that TC copied from (Netguard), there is. Use the one from Fdroid cause I'm pretty sure the ability is neutered in the playstore version. If I remember properly, you gotta set it up through IVP 4 under Network I think.
F-Droid
F-Droid is an installable catalogue of FOSS (Free and Open Source Software) applications for the Android platform. The client makes it easy to browse, install, and keep track of updates on your device.
Matrix space | forum | IRC
Use any DNS you want, the app also has nice logs, firewall, Orbot integration (if you want it), and a bunch of other stuff. It does a lot more than TC.
Rethink uses hardcoded google DNS not respecting your DNS settings for their own calls.
Please avoid RethinkDNS
Do you have a source for that? The only time I see Google DNS requests is in relation to Proton
I use NetGuard and port forwarding TCP and UDP from 53 to 5300 which is used by PersonalDNSFilter. In PersonalDNSFilter I can configure the DNS I want to use
Just use pihole.