FRITZ!Box

You need to setup the static routes like this:

IPv4 network: 8.8.8.8
Subnet Mask: 255.255.255.252
Gateway: (see below)
IPv4 route active: YES

Once done, save the settings, and it will make room for you to add more, you also need to add these:

IPv4 network: 8.8.4.4
Subnet Mask: 255.255.255.252
Gateway: (see below)
IPv4 route active: YES

IPv4 network: 208.67.222.222
Subnet Mask: 255.255.255.252
Gateway: (see below)
IPv4 route active: YES

IPv4 network: 209.244.0.3
Subnet Mask: 255.255.255.252
Gateway: (see below)
IPv4 route active: YES

Below are needed for Netflix only to work on devices.

IPv4 network: 23.246.0.0
Subnet Mask: 255.255.0.0
Gateway: (see below)
IPv4 route active: YES

Pv4 network: 45.57.0.0
Subnet Mask: 255.255.0.0
Gateway: (see below)
IPv4 route active: YES

Pv4 network: 108.175.0.0
Subnet Mask: 255.255.0.0
Gateway: (see below)
IPv4 route active: YES

Pv4 network: 185.2.0.0
Subnet Mask: 255.255.0.0
Gateway: (see below)
IPv4 route active: YES

Pv4 network: 198.38.0.0
Subnet Mask: 255.255.0.0
Gateway: (see below)
IPv4 route active: YES

Pv4 network: 198.45.0.0
Subnet Mask: 255.255.0.0
Gateway: (see below)
IPv4 route active: YES

For the Gateway, use the Internal or LAN IP of your FRITZ!Box (e.g. 192.168.0.1) and add 1 to it. So, if your FRITZ!Box IP is 192.168.0.1, then the Gateway you should use here is 192.168.0.2