Ribbon cables are moving parts. They're not supposed to be though.

My Samsung Galaxy S7 would turn off and wouldn't work again until banged it top down into a table a few times. 3 months later, cracked it open, the ribbon cable was broken ebcause the battery became dislodged. New battery with new ribbon cable, fixed, $15.

Another phone the LCD wouldn't work unless you twisted it the right way. Ribbon cable again. I didn't replace the screen, it would have been $100 I just submitted to insurance for the same price.

These things are literally put together with glue. Leave your phone in the car, glue melts, stuff becomes mobile.

In your case it seems like the daughter board antenna connections are loose.