It would be nice if you lived near me, Plainfield, 07062.
You could borrow one of my 3 Chase RLC-1 Remote Line Controllers that has low volume features that I think will improve things for your low volume listening.
It’s primary function: add these remote control features to any system with manual controls: remote power; volume; mute; balance; treble; bass; select any of 4 line level inputs. Either optional use thru a tape or processor loop, or use thru any line in.
Low Volume Feature: As you lower the volume below it’s default low volume start, it automatically and progressively adds bass boost. Lower a bit more, it boosts bass a bit more. It has many many small increments up or down. Raise the volume, bass boost automatically lessens, and does not occur after you exceed the default low volume start. (note: no treble boost that Fletcher Munson also does).
Setup: Chase at default low volume start.
Your Preamp Volume: raise to your normal volume whereby no bass boost is needed, never change that.
Now use the Chase to lower or raise the volume.
When I listen to Jazz at low volumes, this feature is what keeps the Bass Player audible thus still part of the group, much more enjoyable.
If not a member of hifiengine, you could join for free, then download the manual here, although the bass boost is not well understood.
https://www.hifiengine.com/manual_library/chase-technologies/rlc-1.shtml
here’s one for sale, $135. with the remote which is needed as there are no controls, just indicators on the unit
this expired listing has good photos
here is the inside of one of mine: no moving parts, a single Philips processor does everything, it is noiseless at 105 db s/n ratio. I was adding a toggle on/off switch to the front panel, as the unit has remote standby, but it needs full power off to reset to defaults which I like to do occasionally. Otherwise, unplug it, add a power cord switch, ....
I use one with my Vintage 15" woofers and horn mid and horn tweeters in my main system; and in my office system and in my garage/shop system.

