I use Bluetooth (AAC) daily with Spotify during commute, and at work. It works well though it depends per headset. In general I got good connectivity. It even keeps working when I go grab a coffee so I don’t have to talk to co-workers. though my previous Bluetooth speakers were terrible. I kept losing connection whilst at Amsterdam Central Station.
LTE connectivity gets slightly worse over time due to silver being used. Gotta clean the contacts every once in a while to remove the corrosion.
Are you using Xposed on Android 9? If so, where did you install it from? The version in F-Droid seems to be updated 1 year ago.