Remarkably better sound possible with just 1 system component change?

I could have posted this discussion to a few other categories but chose this one because discussions related to 2 of the 4 components in question belong here.

So it's been ~2.5 yrs since I purchased my current system. I did a lot of research at the time here on audiogon, but no auditioning, and put together a system that sounds very, very good to me.

While I have no complaints, the itch to upgrade has surfaced recently.

I am curious as to whether you guys think it will be possible for me to replace just 1 of my primary 4 components and obtain significantly better sound as a result. The more discernible and obvious the sound improvement, the better obviously. I am not looking for a marginal upgrade - I want dramatically better sound. And I am not looking to replace more than 1 component at this time. I am hoping to get a few ideas/candidates and then may decide to audition some of the recommendations before making a decision. Hopefully some of the upgrade paths are such no-brainers that I may even be able to take a leap of faith without auditioning. Note also that acoustic room treatments are not viable in my current listening location.
My current 4 part system:

1. Lumin D2 - 100% of my listening is streaming via Tidal
2. Mcintosh C2600 preamp
3. Mcintosh MC452 amp
4. Focal Kanta 2 speakers

Cables are Cardas Golden presence RCAs from the Lumin to C2600, Cardas Clear Cygnus XLRs from the C2600 to the MC452, and Kimber 8TC speaker cables to the Kantas.

Soundstaging, dynamics, imaging and overall clarity are all great. I have to say I love the Be tweeters. And the bass is punchy, tight, fast and certainly sufficient for my needs. Vocals and overall sound are warm, liquid smooth and analog-like, just the way I like it. (Forgive me if I've botched some of the characterizations - I'm no expert at this). The only thing I can think of that could use some improvement is the sound quality at lower volume levels, although that is not terribly important to me since most of my listening is in the 90+ Db range. Would be nice, though.

So while I do love the overall sound, surely dramatically better sound can be obtained via a 1 component swap? Budget is ~10k. Or will I need to spend more, or upgrade more than 1 component to achieve the desired result?

Thanks in advance for your time and thoughts.

Room correction with room treatment are the biggest dramatic changes you can make. Anything else not even close, even new speakers. If you can’t or won’t treat the room I’d look into room correction with something like minidsp with Dirac or the antimode products from Dspeaker. Correcting the bass will have the largest impact and will help with the lower volume level listening issues the most.

If your willing to swap amps, go with a lyngdorf amp with room prefect room correction.  Awesome
Post removed 
tomcarr and dbtom2 are spot on. With that room and what you’re using it for, you’re pretty well maxed out in that man cave. Just enjoy what you have and buy some good weed.
OP I know you are happy with the bass and don’t want/need more. Unfortunately, you are missing the entire lower octave so I would suggest a large sub that is flat to 20 or lower. This is not "more" bass, rather, it is missing bass. Just looked at your room... nice! But its a man cave without the man octave :-(
Sounds like you like the sound you have but want better at low volumes. Would keep what you have and add a good powered sub to help fill in the low end. Make sure it is powerful enough to extend to 20 hz in your room and use white noise and a simple sound meter app on a smartphone to get it tuned in to fill in that low end. . Guaranteed big difference at any volume. You should be able to feel the bass not just hear it when it’s in a recording. Few amp/speaker combos have the muscle to do that alone though the bass that’s there sounds perfectly fine.