**wireguard ipv6 creta server**

Unfortunately I speak very bad English, so I try the translator and hope someone can help me!
I have connected a Creta to my Fritzbox 7590 and only use it as a Wireguard server! Recently I have a new phone (Samsung S21 Ultra 5G). Since I use this and activate the VPN tunnel via Wireguard, I have hardly any speed left. I have already activated IPv6 on the Creta and can also see that my phone is connected, but I only have a maximum speed of 2Mbit. I read here in the forum that you have to create a firewall rule,Can anyone help me with what and how I have to do it

Here Screenshots from the VPN (Wireguard):

and here without VPN

no one an idea or can help me?