Hi, the redsocks proxy also has the ability to tunnel DNS over the TCP proxy by configuring a dnsu2t entry in the configuration file as in https://github.com/darkk/redsocks/blob/19b822e345f6a291f6cff6b168f1cfdfeeb2cd7d/redsocks.conf.example#L153
BalenaOS will configure the iptables rules required to redirect all DNS UDP traffic to redsocks:
https://github.com/balena-os/meta-balena/blob/277ddce76f8924e4d115943e1fb842e7f8209f08/meta-balena-common/recipes-connectivity/resin-proxy-config/resin-proxy-config/resin-proxy-config#L87
Maybe this is something you could try out?
Looks promising. If I have time ill try it.