In my old place I had a sub on carpet which was on top of concrete, it was a basement listening space. For years, I had the sub on a guitar amp stand, I think it was called an Auralex Gramma. That helped tighten the bass up from having the sub off the floor, I was happy with that for years.
My curiosity got the best of me and I tried some Townshend bars under the sub and I was pretty shocked at just how much faster/tighter my bass got. More articulate, pretty much all the audiophile buzzwords could be used here to describe the difference in sound. I can sum it up this way, the bars enhanced my listening enjoyment by quite a lot. I won’t be without some type of stand/footer underneath my speakers/subs moving forward.
Good luck in your search! I hope whatever you try gets you to enjoy listening to your system more than before.