The Benchmark LA4 is closest to a “straight wire with gain” that I’ve heard.
No need to spend more if your goal is ultimate transparency and neutrality.
I owned the Freya+ for a time. I tried rolling many NOS tubes in an attempt to hear what all the fuss was about, but alas, it always sounded best in passive mode.
The Freya+ was quite transparent in passive form but the LA4 takes it to another level that I didn’t really think was possible. Remarkably, it doesn’t sound cold or clinical in the process.