Resolving DNS pointing to private ip addresses

I am unable to resolve dns pointing to private EKS endpoints. Yes, vpn's are involved and if I configure my system to route `eks.amazonaws.com` dns requests over the vpn to a non-comcast dns server it works.  However, I feel it's pretty bad behavior to selectively resolve dns if that's what's going on here.

I've called and was told someone would call me back, but they never did. Hoping there might some resolution to this or at least confirmation that what I'm seeing is how comcast operates.

While trying to troubleshoot I've setup some public dns entries that point to private ips (192.168.1.x) and found that comcasts dns servers (75.75.75.75,75.75.76.76) will not resolve those hosts for me. But, hosts pointing to public ips on he same domain DO resolve properly.  This leads me to believe that comcast is filtering dns requests that return private ip address.

I can fix this problem entirely by setting the modem to bridge mode and using my own router/dns. Unfortunately, when doing that it's limiting my internet connection speed because WAN port is only 1Gbs.  If I buy my own cable modem then I don't get the unlimited data.

I need to be able to resolve these addresses for work. Has anyone else experienced a problem like this?