I think I cover some of the bypass bits in the article. In general, there’s not much you have to do other than add a management address.
If you’re seeing poor cable connection, you likely actually have a bad cable connection, or something funky with the WAN port on the router. I’ve seen this a few times, once with one of my Starlink setups, and it actually turned out to be a bad ethernet cable/ethernet adapter on the Starlink side.
There are performance challenges with older Peplink products that cut performance down much lower when cabled versus when using WiFi as WAN, but the BR1 Pro 5G is not one of them. This sounds like some other sort of issue.