There have been numerous people complainin of having bluetooth issues with that phone so I would say it definitely is your phone and it’s software.
1 work around is to clear your phones cache, to do so follow these directions
To perform a wipe cache partition:
1- With the phone powered off, press and hold the Volume Down button and the Power button at the same time until the device turns on.
2- Press the Volume Down button to highlight “Recovery mode”
3- Press the Power button to restart into Recovery mode.
You’ll see an image of an Android robot with a red exclamation mark.
4- Holding the Power button, tap Volume Up once and then release the Power button.
5- Use the volume buttons to scroll to “wipe cache partition” and press the Power button to select it.
6- “Reboot system now” will be highlighted, press the Power button to select it.
It may take a few minutes but once done your phone will restart ad then try and see if it’s still an issue