I deactivated ipv6 because pihole wouldnt block ads on all devices. I even needed to call my ISP to deactivate the ipv6 dhcp because i cant change settings in my router.
Edit:
Okay, after some google searches i found out that, it was not because of ipv6 but because of the blockingmode. After putting the blockingmode to null it fixed the slow loading!
Normally it wouldnt take so long to load a website. I waiting 30 seconds for a website to load completely. That did not happen before i deactivated ipv6.
Since your debug log suggests you are using Pi-hole's DHCP server:
Please try disabling Pi-hole's IPv6 support as well - your debug log shows it to be active still: