Tube preamp recommendation ...

With regard to the Dodd buffer, note that it is a passive which can be highly system dependent. Very transparent, but a passive can also have diminished dynamics, drive and oomph. This is what I found with the Dodd in my system, though in other respects it was excellent. If I were to go passive, it is likely what I would choose. But for me, a quality active pre wins out. You do need to spend to get the level of detail that a passive gives, but I find it worth it.

I love 6SN7s so a Cary preamp would be my recommendation. You can find good NOS/OS tubes to roll in order to fine tune the sound to your liking.

Look into Purity Audio...their pieces are getting a growing amount of attention and fit your description...

CJ and ARC are two very different animals from two opposite ends of the spectrum. The CJ will give you the musical and warmth that you seek, the ARC will give you the transparent and neutral that you seek.
If you are looking for something in between these two polar opposites, you might consider a previously recommended Joule Electra or a VAC Renaissance or Signature preamp.

Conrad Johnson Premier 16.