Since my last post, I've updated to 11.2.5. I had high hopes for this! However, it seems that it has not fixed the problem ** randomly disconnected bluetooth.
While 11.2.5 is much faster (user interface wise), it still did not rezolve the bluetooth issue (and the wifi issue which occasionally does not work).
As I previously said, it is a matter of bluetooth in general, streaming music to cars, or bluetooth headphones, connected devices such as smartwatches, etc.
Since the problem is pretty random, I cannot safely say that the disconnects happen more rarely than 11.2.1 or 11.2.2.
Sometimes it works for reasonable ammounts of time, sometimes, it keeps dropping (especially annoying with music) every less than 10 minutes.
So far I have been able to identify that if all apps are stopped, the music (via BT) does not interrupt (this is my particular case with an iPhone 6S).
I was able to identify that while listening to music via BT and using Safari to browse the web, the interrupts almost surely appear.
As I previously stated, I've done EVERYTHING recommended from forgetting devices and reattaching them, to resetting network settings and ultimately restoring my iPhone AS NEW IPHONE thus losing every setting and slowly installing and configuring everything back (email, wifi connections ...others) MANUALLY !!!
I listen to my Bose Soundsport Headphones a lot, always have them on me, and had them prior to IOS 11.2.x. Never have they glitched once, in simillar conditions as now (same BT devices that I have now).
Also, I have tested my headphones with an Android Device, and an Iphone 5S running IOS 10.x.x for days at the time, and there were NO DISCONNECTS at all.
While this problem is especially annyoing with music, since it interrupts songs, it also happens with my smartwatch (though since it automatically reconnects in about 10 seconds it is not as annyoing, seeing as it does not affect a continuous process), and also to my Plantronics headset that I use to speak to collaborators and clients. In the middle of a conversation, BT just drops and they no longer hear me, and by the time I realize it has swiched to my phone, sometimes they hang up. Very very annoying.
I am growing desperate!