I host my tuwunnel server and I am happy with it. The lack of a top level client is my turn down. Element X is good but still lacking, and fluffy chat is maybe better looking but more lacking.
My matrix use case is only WhatsApp and telegram backup using the bridges, actually... So YMMV.
Just a normal 4 people home, two teenagers tough. Enabling a DNS resolver indeed stop working after a few days while setting it up as forwarder to 1.1.1.1 or 8.8.8.8 or pick yours works just fine.
Maybe it's something else, but when it happens, that's the feel
Changing "DNS" won't fix it. There are two DNS: dnsmasq and inbound (and bind, ok). What else you use doesn't matter (pihole, adguard, opnSense) at the end of the day it's always them inside.
In my experience ISPs will block your direct DNS queries overtime, so it might be that. I set up my unbound as caching and forwarding, not as a pure resolver. This fixed all my issues with DNS self hosted. You can forward to 9.9.9.9 if you like it.
Another issue might be with your blocklists of course, your azure might have been temporary listed maybe.
Over time I ended up choosing a very lax blocklist setup due to this reason
Self host dokuwiki. Simple, easy, effective. I do.