I have literally the same problem in my iphone 11 and my phone is brand new, thought they would solve the issue with the update but still the same, i tried everything i don’t know what to do it’s frustrating

Guys i just figured it out that bluetooth works fine only if you keep your phone connected with the power charger, otherwise the problem persists, this is insane and obviously a software issue.

i just installed ios 15 public beta and the problem is finally solved! i'm nearly in tears

Problem fixed in ios15