Over Tubing it?

I am pretty sure this has come up before, but I am wondering folks opinions on whether one can "over tube it" with integrated amp and DAC.  I have a tube integrated amp (Black Ice Fusion F35 with KT-150s) which I quite like and wish to keep.  I am now auditioning the Denafrips Ares 2 DAC and my Black Ice DAC which has tubes.  

Anyone have thoughts on whether staying with the Black Ice tube F35 amp, and tube DAC, versus replacing the tube DAC with R2R (e.g. Ares or Pontus) or other for maximum quality, paired with my tube integrated amp? (Quality meaning 3d holographic soundstage, transparency, detail and other buzz words), etc...

Put another way, what do you all think the best placement of tubes in the chain yield the best results, and is it possible to "over tube"?

I stream via roon server and Optical Rendu exclusively.

Would love to hear the community's thoughts and experiences with this.

Thanks a lot.