DNS over TLS/IPv6 issues- Apps don't load data over Wifi

Good morning everyone,
I was very pleased to read that /e/OS is now getting a fix for this, and I really hope it comes to Android 16 as well. I’ve tried all the tips shared here, but nothing really works; the problem returns after a short while.

I’ve tried the following in conjunction with my FritzBox 6670:

Different Wi-Fi versions (Wi-Fi 4, 6, 7) – no success
Tested different WPA versions and settings – no success
Disabling Wi-Fi frequencies (i.e., using only 5 GHz or only 2.4 GHz) – no success
Disabling DHCPv6 (for IPv6) and running only IPv4 – no success (see image)

Tried the function shown in the image – no success

Disabled Private DNS on the smartphone – no success

The only thing that actually works is disabling IPv6. At work, we have a Wi-Fi network that runs solely on IPv4, and I have absolutely no issues there. The annoying thing, however, is that if you have a Dual-Stack (DS) connection, things don’t work properly when you disable IPv6. That’s why I really hope the issue gets resolved quickly and reliably.