Do I REALLY need preamp and what do I upgrade the amp too?

Tubes are an acquired expense. If you can't think of a reason for needing a preamp it is safe to say you don't..

I have a different setup to yours of course, but in my experience, a high-end pre adds magic, smooths out edges, sweetens midrange and anchors the bass. Of course everything is synergistic, right combo of tubes amps, the pre, source and cables, but in my system, the pre is a must.

Does it sound great without a pre? Yes, but it sounds, in my attempt at something meaningful, about 12% better.

Maybe get something from somewhere that has a long return window and low restocking fee and audition some stuff.

T

You have a vaulted ceiling, have you measured your in room FR? I would not drop $ on gear if you don't have the response curve you want in that room. You can hang acoustic clouds to offset the ceiling reflections. 

Typically running a DAC right into an amp will give you great clarity but be drained of the soul… the musicality. As many of us experienced audiophile say the preamp is the heart of the system, where the magic comes from. High quality sound can be gained by direct connection, but it is incredibly difficult (component matching) and expensive to do.

My rule of thumb for a well balanced optimal system the investment level of all the electronics is roughly the same… Streamer = DAC = Preamp = Amp. If I was going to put extra on something, my first choice is the preamp. A regular integrated amp’s investment is divided by two… since it is performing two functions.

I would look at your system this way, upgrading each component with a target level in mind. Typically I would start with the preamp.