Restarted the router, Android device, laptop, in Windows 10 flushed dns and cleared DNS cache inside of chrome. Same results.
Edit:
To flush DNS in chrome and brave I've used chrome://net-internals/#dns, also I've DNS caching enabled on the router, but that should be cleared on router reboot. As WAN DNS I use Google DNS, for DOT I use Cloudflare, so I can make sure when I see Cloudflare on dnsleaktest.com I go through DOT.
Edit2:
Cleared all side data of rootcanary through chrome developer tools in Windows 10. Same results.
Edit3:
It gets even weirder, the Android device I mentioned above is on Android 7, if I use my phone which is on android 8, Brave and chrome behave the same but now all red in the last column except for the gost row. Booted up another PC with chrome and Brave, did the same cache clearing and now also the last row shows red... Must be some caching going on. Whatever I do my laptop with chrome shows green results in the last column.
Edit4:
Sigh... After all the DNS flushing and clearing site data, ctrl-F5 did the job on my laptop, so clearing all site data does not clear everything in chrome developer tools.... Now the result on my laptop shows red also. So Cloudflare probably does not support ED448.