You seem confused between two quite different Bluetooth functions.
Pairing and connecting. I do not see why one would need to un pair and then do a new pairing if one has connectivity issues. This sounds like the advice an Apple "genius" might suggest. Perchance your anecdotal experiences with Bluetooth connectivity are due to subpar Apple hardware.
It seemed pretty clear to me.
Simply put, my pebble watch was technically paired to my iPhone, but I wasn't getting notifications pushed to my watch. The only way to fix the problem was to repair the watch, by first "forgetting" the connection in the bluetooth section of the settings app, then repairing it all over again. And even then, I ran into occasions where the watch simply failed to pair again, resulting in a fair amount of frustration.
And while we are on the topic of the pebble watch, that thing had pretty bad build quality. The charging pins had a habit of corroding pretty easily when exposed to sweat, leading to my watch not charging unless I scraped away the layer of corrosion with a fingernail, and of course, this was just kicking the can down the road.
I know - it costs just a fraction of the price of an Apple Watch, but I guess there is some truth to the saying "You get what you pay for" at the end of the day.
Same with my wireless headphones (Jabra). Once in a while, it would just fail to work, and my only real solution was to erase and repair it again, like what I did with my Apple Watch.
Perhaps it is, like you said, due to subpar apple hardware. But my anecdotal experience has been that my "subpar" iPhone, my "subpar" Apple Watch and my "subpar" AirPods, have proven to be far more reliable when used together than when it was just my iPhone + pebble watch + third party wireless headphones.
So the sad reality was that for me at least, these supposedly superior third-party hardware (as touted by some members here) wasn't offering me more of what I wanted (a seamless integrated experience which just worked right out of the box), but was instead saddling me with more problems and more frustrations that I had to contend with.
Which brings me back to my original point - specs don't matter. Only the end experience does. That is the truth I have learnt after having used Apple products all these years.