Bluetooth intermittent signal

Hi...would like to ask how to troubleshoot my iphone 6s bluetooth connection with my Airpods. Seems like intermittent signal from my iphone. Already checked the airpods but no problem with the airpods (try with other iphone). Also tried to connect Jabra Elite 65t to my phone.. same problem...intermittent signal....

Already do hard reset, reset all networks....forget device... just not yet try to erase iphone to factory setting. this happen when im updated my ios to 12.4.1

Any suggestion how can i solve this problem?

thanks