Sheer curiosity forces me to tag in here.
Its suprising to hear someone say VAC is more so about the mids than extension in either direction. This could be said of many tube amps I suspect. Sorry, just thinking out loud.
If SS attributes are an inclination, maybe something like the Pass labs 30s or 60s XA series. ??
Wouldn’t it be safe to say then the output tubes attributes might be the key when seeking a tube amp solution which yields better evenly distributed bandwidth presentation?
I can only say from EXP EL34 & the Russian output tubes BAT prefers aren’t what I would call great bottom end providers. Past those, I’m clueless as to which others can do better. I only suspect KTs may.
Sorry I can't be more help. Good luck.