For test I would bypass it completely as it might be the problem.
Do not use AdGuard, configure 1.1.1.1 directly in your OS.
If you Google you will find quite few cases when B2 IP addresses were blocked by some “clever“ DNS solutions. Just forget about “cleverness“ for a moment:)
credit goes to @asdffdsa who from the start suspected DNS
I have to admit that 0.0.0.0 returned IP address is something I have never seen before. And I suspected that things should be more black and white in case of DNS. It works or not.