OP, this is trivial to detect. DNS command and control is a thing malware/attackers use which among other things include TXT records,DoH, long A or AAAA records

OP, this is trivial to detect. DNS command and control is a thing malware/attackers use which among other things include TXT records,DoH, long A or AAAA records and many other creative ways, my fav right now being using a CNAME chain to encode information (no single request is too large or suspicious. In my experience, bypassing censorship does not mean doing unusual things like this but things like browser extenstions that stego your message in legitimate requests .