I’d recommend taking a look at the Linear Tube Audio MicroZOTL tube preamp. I believe they offer a 15-day trial so you can see if it works for you. Here’s a review by A’gon member Terry London in case you haven’t already seen it…
https://hometheaterreview.com/linear-tube-audio-microzotl-preamplifier/
https://www.lineartubeaudio.com/products/microzotl-preamplifier
Best of luck in your search.