If you want to manually update your system to Android 11, you need to update to the latest A10 firmware version first.
Download and install the WW-17.0823.2104.147 firmware package.
Download and install the WW-18.0410.2106.138 firmware package.
You should now be able to download and install the latest WW-18.0410.2111.185 firmware package.
To manually update your device, please download the manual update file and place it in the root directory of your device, then reboot. When your device boots up, it should detect the zip file and ask you to update.ROG Phone 3 | Gaming Phones｜ROG - Republic of Gamers｜ROG Global
I can see that you are currently running very old firmware, which makes me suspect you've been sold a Tencent device intended for the Chinese market, which has been flashed by your reseller before you buying it.
This is an unsupported configuration that we can't guarantee will function properly. Because of the model/ROM mismatch, you won't be able to receive automatic updates, for example. If you run into any issues with your device, please contact your reseller.