My UDM SE is configured to get its DNS from an Ubuntu VM with Adguard Home installed which I have deployed in Oracle Cloud's free tier. I have the Oracle Cloud security set to only accept requests from my static IPv4 address, as well as my /56 IPv6 range, plus 443 and 22 again from my home addresses. I then installed certificates on it and enabled HTTPS. Its forwarder is set to Quad9 only. I've never had a single issue with it since deployment and it's super fast. If it breaks I could have it back up within 30 mintutes as I've saved all of the steps I did.