Using Pi 3b+
Recent re-install of Pihole (Previous install had Nextcloud installed alongside Pihole, removed Nextcloud to another computer), and added Unbound.
Changed Admin page link to go to port 8080,
Expected Behaviour:
"Status" line on Query Log to show "OK - Cached" (previous install did this) or similar
Can you run a few dig or nslookup runs against a single domain and see what is shown for response times and for the web page log?
It's quite possible that the domains you are looking at have very low TTL values and are in the cache for short periods of time. (5 seconds or less for some major sites)
You can try dig pi-hole.net a few times and see if the query response times drop on the additional runs, and then check the web interface to see if the additional ones are coming from cache.
That's not querying Pi-hole, that's going to your upstream.
If that's the Pi-hole server itself then you can directly query with
dig pi-hole.net @127.0.0.1 or dig pi-hole.net @<PI-HOLE IP>
You need to run it a few times though, the first time it probably will go to unbound and you'll see a query time in maybe 10-100ms. Run dig again and it should show a query time of 1ms or 0ms and that shows it's pulling from cache. Run dig a third time to see even more of this.
After you've done that then check the web interface to see where the queries went, it should just confirm what we've already found out.
A request only shows as cached if at the time of the request, the domain was in cache. Cache entries are typically for 5 minutes or less (the duration of most TTLs). If you have a new request more than the number of seconds specified by the TTL later than the first, the second request won't be in cache and it will be forwarded to the upstream DNS server for resolution. In this case, Pi-hole forwarded it to your local instance of unbound, as expected.
ok, so, after getting my head out of my nethers - I redid the dig command, as you showed (and I somehow managed to ignore)....this was after run number 6
The TTL for the A record for pi-hole.net (per this website, for reference) is 900 seconds (15 minutes). Depending on which upstream DNS server you use, it may be less than that in your reply from the upstream nameserver.