hello Fayorg
Welcome to the community.
I doubt, you will be able to use the XGS-PON ONU stick directly to bypass the Sunrise box.
In order to use your UXG with the Sunrise Box, your public IP address needs to be a public IPv4 address. To see what type of IP address you get visit https://test-ipv6.com/ If it is a IPv4 fine, if not you’ll have to call 0800 707 707 and request a change to IPv4. Please wait for the IPv4 change to take place before applying any settings.
By default your Sunrise Box should use the subnet 192.168.1.0/24 for the LAN. If you like to change that, instructions can be found on section 8.2 on page 89 of the manual.
As I don’t know what settings you’ll use, I will state everything with default settings. The Sunrise Box has the LAN address 192.168.1.1, DHCP range is 192.168.1.2 - 192.168.1.254. DHCP range should be changed to 192.168.1.10 - 192.168.1.254.
In order to set the internet connection on the UXG, you’ll have to logon to the local GUI of the UXG and edit the settings there. Make the WAN connection static, the WAN IP of the UXG will be 192.168.1.2, the subnetmask can be set to 255.255.255.0 or 255.255.255.252 (I prefer the later, it tells the UXG that there are only two devices present). Gateway will be 192.168.1.1. DNS can be set to 192.168.1.1 or you can specify other DNS you prefer.
Keep in mind, the default (V)LAN on the UXG needs to be changed to something different then 192.168.1.0/24.
Back to the Sunrise Box. Now set the DMZ for the UXG (192.168.1.2). You can follow the instructions in section 11.4 on page 117 of the manual.
By now your UXG should be online and usable. You might want to turn of the WLAN on the Sunrise Box, since you want all your traffic go thru the UXG.
Here’s the link to the User Manual of the Sunrise Box.
Happy networking