Although it has been quite a while since you posted this it would be a shame if i go through this thread and don't appreciate the sheer effort you have put in this highly detailed review.
So congratulations on this outstanding review and great pictures too! You should have been paid a decent sum for something like this but then you might loose this passion with which you have crafted this.
Coming to the bike itself, incidentally i have riden the Himalyan quite a bit as my cousin owned one, we both purchased our bike almost in the same time frame and swapped rides a couple of times. (His was a BS4 purchased in early 2019)
While i'am no fan of Royal Enfield for their ancient tech and the ADV segment in general, i couldn't bring myself to dislike the bike for what it is.
The lack of tech is made up by somewhat reasonable pricing and having that cleared up the bike works really well in a wide variety of applications. For one it is like a SUV of sorts that it can take all sorts of roads with ease and comfort. No problems there.
The power is adequate and rather enjoyable in the low end and midrange and if you don't push it further you will never find it lacking anywhere.
The usual RE vibrations are also excellently controlled and even in my brother's BS4, the overall refinement till around 6000 RPM felt smoother than my R15v3 till that point, ofcourse my bike revvs much further but its a revelation of sorts, i found its refinement to be very similar to the BS6 you write about rather than the BS4 you encountered, perhaps that unit was abused.
It wasn't without its issues though, the bike used to randomly stall, even at idle when cold, and this is not in winters mind you. This was a first for an Fi bike. It even had a choke which i found really amusing.
Then there were engine head problems wherein he had to have the engine head replaced at around 2-3K Kms and when he came with me on a ride after around 500kms driven in his new head i noticed the new one leaking massive amounts of oil, he repeated this process 2-3 times before eventually getting bored and selling off his bike.
He tried adventure riding and found the bike to be too heavy and did not enjoy it, i had warned him about all of this though but he learnt the hard way, i must add he was a novice rider and this was his first bike, someone else might have a different experience.
But then again, i usually dislike ADV styling and the segment in general but as a second bike this works well in one's garage and i don't dislike it at all, despite being simple and not my type i still feel it looks international, different and not bad.