Hi @tommytom_,
Does the WiFi have the same problem?
Just asking as the BT and the WiFi are in the same IC.
If using WiFi, try using the phone as close as possible to the network router i.e. <10cm, the same with BT to the other BT device and check if it works OK.
If so there may be a problem with the antennas in the phone, loose perhaps
Here's an image from a teardown video that may help, showing one end of the two antennas in the phone.
(click on image)
crwdns2934105:0crwdne2934105:0
crwdns2934113:0crwdne2934113:0
crwdns2915270:0crwdne2915270:0
crwdns2889612:0crwdne2889612:0
1