I noticed that loading the web interface is taking long time to load. the below cURL output confirms this behaviour even when connecting through HTTP. This behaviour for the initial page load only, other APIs and assets are taking milliseconds to load.
Connecting to HTTP
$ curl -o /dev/null -s -w "DNS lookup: %{time_namelookup}s\nConnect: %{time_connect}s\nSSL Handshake: %{time_appconnect}s\nTTFB: %{time_starttransfer}s\nTotal time: %{time_total}s\n" --resolve pi.hole:80:127.0.0.1 'http://pi.hole:80/admin/'
DNS lookup: 0.000079s
Connect: 0.000580s
SSL Handshake: 0.000000s
TTFB: 0.001824s
Total time: 5.027472s
Connecting to HTTPS
$ curl -o /dev/null -s -w "DNS lookup: %{time_namelookup}s\nConnect: %{time_connect}s\nSSL Handshake: %{time_appconnect}s\nTTFB: %{time_starttransfer}s\nTotal time: %{time_total}s\n" --resolve pi.hole:443:127.0.0.1 'https://pi.hole:443/admin/'
DNS lookup: 0.000106s
Connect: 0.000708s
SSL Handshake: 0.267695s
TTFB: 0.268891s
Total time: 5.293133s
Debug Token:
Debug token is: https://tricorder.pi-hole.net/c4zWS0rF/
Core v6.0.6
FTL v6.1
Web interface v6.1