Thanks, good to know! I'd suggest including this warning in the setting description until it is fixed.
I know you only get it in "All settings", but even as an expert user, I somehow expect them to work 
In the config above, you are missing the /api endpoint. If it's working, you most probably had it in your config, but didn't paste that part. That makes discussing more difficult
Great! Yes, that's the easier setup.
There's a subforum for it: Feature Requests
It was the case for v5 and there still seems to be a bug in v6 with redirects: Pi-hole 6.x: Links redirect to admin panel instead of being blocked