I have learned my lesson! Edge dropped phone. Display cracked , force created a hidden micro crack in the back glass. I heated the back very well, but still that thing cracked as I was finishing. Take my advice, and anytime you work on this phone buy a new back, then just break off the current one. You will be sooo much happier. Don’t forget to make sure it comes with adhesive.

I was trying to nail down the bluetooth location and reason for weak signal. You did mention the chipsets, but some comments on antenna routing and service would help. Regardless, thank you for this !!

translated; In the event of poor WiFi reception, it may be sufficient to pull out the plugs and reinsert them, and to open and close the screws of the WiFi antenna a quarter of the way. Why: The antenna can hardly break, most of the time there are contact problems. As in my case!