@cat_doorman
Hattor has a nice looking tube buffer meant to be used with their passive preamps. It might have some fixed gain though. I’m not sure if that can be defeated, bypassed or altered as an option.
I own one of those and they sound very nice. The default is 9dB gain, which really isn’t that much but Arek can build them to your specification. We compromised and mine has 6dB gain.
I spent some time trying to find a preamp with little to no gain, even started a thread on it here, but eventually broadened my search. While I didn’t need any gain, getting a little hasn’t seemed to hurt anything.
If you want a great sounding preamp with no gain, the SMc Audio VRE-1 C comes with 6dB gain through the transformers. However, I believe Steve can build it with unity gain as he did with my modified TLC-1, which I use as a unity gain buffer along with the Hattor passive, which provides volume control and other convenient functionality.