I looked to see if the OpenWrt software or any modem supports DoQ and I saw something like this.
"QUIC is a horribly complex protocol to implement, requiring rather large libraries and forced cryptography to deal with it, making it unsuitable as default choice for weak devices."
I looked at Adguard, NextDNS, Cloudflare and Quad9, which provide DNS services, and they provide the DoQ service through their own applications.
I think providing support via modem is a bit problematic.