In what way? Do you want your router to expose a DNSoTLS endpoint to your router's clients or do you want your router to use DNSoTLS to fetch its results?

Both are technically possible but probably a lot of work if it must run on off the shelf router because the firmware choices are pretty limited. It might be easier to run your own DNS server off a Pi (or something) and have your router point your clients there.

Alternatively install OpenDNS Umbrella which will do this with DNSCrypt to the OpenDNS servers