Is Sub Gain Set&Forget Across Music Genres a Fallacy?

I have a single subwoofer in each of my 3 installations.  Two Rels (S/5 and R-328), and a Sunfire (SDS8).  L/R's are Spendor D7, D1, and SA1, respectively.

Try as I might, I cannot ever seem to arrive at one sub gain setting (to say nothing of crossover setting, but let's leave that alone for now) that works ideally or even sufficiently for all of the music that I listen to (blues, jazz, rock, classic rock, southern rock, country, some pop).

Maybe I'm naive and the answer is simple - of course dummy, why would you think there'd be a single setting that would work for everything?  

It'll sound perfect for certain songs/genres (majority), but then I today listen to Jimmy "Duck" Holmes new blues album "Cypress Grove" (really good), which has a TON of bass (and really good recurring bass on certain tracks - probably a pretty good album for sub setup) and I find I need to dial everything way back.

So if I say, okay, this Cypress Grove album is my baseline for setting up my sub, then it'll probably come up wanting on other stuff, ugh.  I am going to get some GIK room treatment monster bass traps to go on the front wall, so I know that will help.

As I said, maybe the simple answer is, YES, there is no such thing as set and forget for subwoofers across music genres.

PIA to keep changing the gain during a listening session but appears that is way it has to be if I don't want to just ignore the non-ideal-ness of the bass with single setting (not my style).....    If that's wrong, LMK what the magic secret is!  

I anticipate some will say multiple subs is the only way to cure this.  Perhaps, but not an option at present time for me.  Looking to keep this discussion to single sub if possible, as I know it could easily morph to a swarm discussion quickly. 

If sub swarm is the only answer, however, I suppose I could accept that.  But if room treatment and careful setup can get there, that's preferable.  Maybe set/forget not even possible with swarm - kinda seems like this could be an issue that more subs don't necessarily fix?