Your request is definitely not for the faint-of-heart. Go to YouTube and search for Nater Tater and the many videos he’s created about modifying the T-Mobile gateways.

It sure would be a lot easier if there was simply a USB-c receptacle on the back of the gateway to plug in an external antenna. But as John Belushi used to say on SNL, “But NO-O-O...!”

For wifi extension, I just use some cheap TP-Link Deco mesh units in access point mode… works great.

did you see this: Post on Bucket