Your debug log looks normal with regard to Pi-hole's web interface, showing lighttpd has been chosen on installation and is listening and properly answering requests:
*** [ DIAGNOSING ]: Setup variables
INSTALL_WEB_SERVER=true
INSTALL_WEB_INTERFACE=true
LIGHTTPD_ENABLED=true
*** [ DIAGNOSING ]: Ports in use
[80] is in use by lighttpd
[80] is in use by lighttpd
*** [ DIAGNOSING ]: Dashboard and block page
[✓] Block page X-Header: X-Pi-hole: A black hole for Internet advertisements.
[✓] Web interface X-Header: X-Pi-hole: The Pi-hole Web interface is working!
However, it seems like you've recently changed your configuration with regards to IPv6, as your Pi-hole shows blocking, but only zero requests in stats, and your previous screenshots show an IPv6 ULA address in use, where your debug log now shows only a global address.
Note that a ULA would be preferred, as Pi-hole needs a stable address, while a global IPv6 may change over time for various reasons (see also Use IPv6 ULA addresses for Pi-hole).
That limits the problem to your PC, making it very unlikely that this is a Pi-hole issue.
Check if something on that machine blocks access to Pi-hole.
Your browser may mistakenly restrict access to Pi-hole if you are using ad-blocking extensions, or some anti-virus DNS feature may interfere. Still, this could only explain why your Pi-hole isn't accessible by its hostname.
And unless a local firewall on your PC blocks Pi-hole's IP, access by IP should always work, the only exemption being use of a link-local IPv6 address (fe80::) when Pi-hole and your PC would reside in different network segments (which would be uncommon, but not impossible in a home network).