Apologies if this is an obvious question, why would the 65t’s sound considerably louder connected to an iPhone Xs and Apple Watch 3 and annoying quiet with an LG v30 phone?
Thought it might just be Bluetooth 5.0 (or the lack of) causing the difference but the Apple Watch doesn't have Bt5.0 and plays at the same decent volume as the iPhone
try this, it may (or not) make a difference on the volume problem:
with the 65t connected to phone, enter your Bluetooth settings, and click the three dot to enter a menu, then turn "media volume sync" ON . then turn up the volume on both your phone and eartips to maximum (careful not to let anything playing or you might blow your hearing).
after that, turn "media volume sync" OFF, and put the earpieces inside the case to reset. in my case it helps increase the volume on the 65t