Tube preamp for my Bryston 7B3

Might look at Rogue RP series. Good value stuff. I have had the RP-1 for several years and really have enjoyed it. Put in matched Mullards from Andy at Vintage Tube Services. Match that with class A/B solid state amp and Focal 926.There is an RP-5 over on USAudiomart.
RP-9 on herehttps://www.audiogon.com/listings/lisabe08-rogue-audio-rp-9-stereo-tube-preamplifier-rp9-black-34670...
I had a listen at Octave at RMAF a couple years ago and their stuff is way impressive.
https://www.octave.de/en/htdocs/verstaerker/hp300se.php
Octave also has this baby for even bigger $$ but very cool.
https://www.octave.de/en/htdocs/verstaerker/hp700se.php

If you have not done so you might check here at the Bryston forum on audiocircle.com

https://www.audiocircle.com/index.php?board=57.0

PS Audio BHK Signature Preamp has input stage tubes.  And they might even have a try and buy on that model.
https://www.stereophile.com/content/ps-audio-bhk-signature-preamplifier