Are you 100% sure that you were on the hotspot, with an IP address and DNS coming from the hotspot and the Windows machine absolutely not using your home network? For example if you have hard coded Pi-hole as the Windows DNS, this test is pointless, it has to be completely off your home network and on the hotspot so that you are removing all home elements, apart from the Windows machine, (Pi-hole, Unbound, router, ISP) from the test.
The Windows machine itself seems okay since the issues it's seen are also being seen by the Pi-hole OS, ie Windows itself appears to not be relevant and can therefore be used for the above testing with good confidence.
Your lookup tests and earlier log show:
- querying against google
8.8.8.8worked
- querying against a public AWS server (same one debug log used) timed out
- querying against cloudlfare
1.1.1.1worked - querying against quad9
9.9.9.9worked - querying the txt record for ATLAS against the A root server timed out
- querying the I root server timed out
These results are not tied to Unbound, your Pi-hole OS or Windows. There really is something external causing those timeouts. As a result of those timeouts, Pi-hole cannot access infrastructure it needs (eg AWS DNS) and Unbound evidently cannot perform recursive lookups.
Correctly testing on the hotspot removes all the home elements and apparently just leaves a regional cause. You may wish to try powering off all your home kit (router, Pi-hole, extenders) so your home network is offline, and then try the hotspot test again with a different machine if you have one. You can then be sure your home network is not involved in the testing.
Other than that, I'm sorry but I'm out of further ideas. It doesn't look like a Pi-hole or Unbound problem per se; rather, something else is preventing access to certain external servers and this is preventing Unbound from working.
At this stage you may prefer to ditch Unbound and set your Pi-hole upstream to a privacy-focused external resolver such as Quad9's 9.9.9.9. Note that this won't fix any issues where Pi-hole or its OS cannot access AWS DNS servers, but at least you will have ad blocking and good privacy during normal use.