The https-dns-proxy package was breaking my internet, I fixed it by simply replacing Bootstrap DNS. Now everything works for a few hours, and then the Internet breaks, something does not load, and something continues to work, an example of a game. Restarting https-dns-proxy helps. Router: Cudy WR3000S. Openwrt 25.12.4
Ssh to the router after internet going down, run dmesg to see system log, look for most recent entries (they'll be the last ones printed).
Try pinging you DoH servers, report back.