Questions about a new Ruby 2 cartridge

I used the Ruby, too.
It needs about 50 hours playing time.
First it is like you wrote but it will become better and better. After 100 h it is great.
all new cart. need some playing time, some more, some less.
Your 47 k setting is the right one ( when other
setting - lower- sounds better, then is something wrong in your system ).
In your manual from the Klyne there is the right setting listed.
Definetly, VTA is important, I used it a touch higher in the back.

47 k load

Well, it is a point of view like the opinions about best speakers, best amp and so on.
From my experience with top equipment the last 10 years I went always back to 47 k load for most MC carts, there is the most information, FM Acoustics has a input module for 100k.
I tried a few times with adjustable phono stages, when, the more I went down from 47 k, the less information was heard. Right, as long you use something above 1K it is not that inferior, but below 1K it is easy to find out, when there is a good, open system.
I always wondered about recommendations for whatever, say 45 ohm, or 122,5 ohm or 187 ohm, reviewers like to do that, to show their ' competence '.
The only way I can imagine, that this sounds good, is, when someone owns a very analytic system, which normally is not a joy to listen to. Here the damping and cutting the high frequency information is indeed a argument, that this setting sounds good, it sounds good in their sharp systems.
A 47K load is in these systems not a joy, because most think it is too bright and overanalytic, no analog ' warmth'.
Next is, phonostages which work the way they should ( not dead and lifeless ) with MC and 47 K are extremely rare, they are very difficult to design ( CTC, Klyne, Vendetta ....), so most manufacturers make more 'advertisement', that this ( 47K ) is not useful, theirs- maybe 50-250 ohm - are ok for all systems.
And that is nonsense.
I don't want to start a discussion about that, everyone thinks maybe different, it was just my experience form my systems and from a few others, which sounds really good.

I did try it again with different settings and it was always the same: down from 47 k, it will be becoming slower and slower, more dull and lifeless.

But there is another point:

When the gain is set too high for your cartridge, you over-drive the amp stages and clipping and distortion is possible.

I did all with my Miyabi, 0,25mV

( this is low output, but not really low )

When I went too high with gain ( 67 dB and more ) in combination with 47k, then I hear clipping with piano recordings.

Going down to normal 63 dB area,then everything is great with 47k.

I think, most users set their phono stage to the max gain and then they do their ' experiments '.

Wrong way.
I had a Ruby, too, it is designed originally from Benz ( not Lukascheck ) for 47K.
The new Ruby II, which has a higher output, i think, something in the 0.4 mV area ??, when this one is amplified with too much gain ( 64 dB and much more- 68,70,75dB) and a 47K setting, this will be inferior. So I agree, when someone with such a setting is going down to 1k, that the prefers that.

The superiority of a 47K load ( in a phono stage which can handle it without sounding dead ) is only in combination with the right gain for the cartridge.

For those, who own a adjustable phono stage ( gain, impedance ...) and a uncoloured system it is easy to find out.