Are there any $1500 tube preamps that that can compare with Tubes4hifi's SP14?

The Freya preamp should be on your shortlist, especially considering all of it's features: fully balanced, stepped-attenuator, selectable passive/j-fet/tube buffer, and remote control. Only $699.

Thats a lot of cool features for that price.

I think I’m most interested in the imaging and the details on the highs. Theres a little muddiness in the midrange but that’s not bothersome. The AI is very musical and sweet and I do want to keep that quality.

Here's my rig:

Magnepan MG .7
Audible Illusions Modulus 2d
Bryston 4b-st amp
Rythmik f12 sub
Bluesound Node
Tidal streaming

Your amp requires 1.4vrms to reach maximum power.  Your sources are all digital which means you are already above 1vrms into your amp.

Let me pose the the question of why do you need a preamp?  Adding amplification that will be deamplified via the volume control can only add distortion.   Have you considered using a DAC with a built in volume control or a passive volume control such as a transformer volume control