Advice needed on Amp

You could upgrade the amp to something like Parasound A21 (which would definitely be an improvement) at something like $1800 used.  This would definitely increase the resolution/transparency.  I would also look at your interconnects, as solid-core OCC copper (like Audioquest) can improve things.  Look at Music Direct because they have many on special closeout pricing (such as the Columbia or Colorado), or look for a used King Cobra.  Another option is Wire World interconnects, which are very nice, maybe like the Silver Eclipse 6 or 7.

Speaker cable - look for used Audioquest Rocket 44 or 88 (or anything above that).

The Jade 5 speakers can be bright/harsh sounding because of the aluminum done.  If this is a problem for you, maybe look for something different.  I have found that speakers that use Seas magnesium drivers are very high resolution and transparent (for midrange and early highs).  Something like Tyler Acoustics Linbrook Monitor.  Or look for a Salk speaker using the Seas Magnesium.

There are other speakers that uses Scanspeak drivers which can be said to be very high resolution and transparent.  Wilson Audio (super expensive) or Odyssey Audio.  In my listening, the Scanspeak are very transparent, but they have a harsh sound in the highs and I think they sound somewhat hallow.  You'll really have to listen yourself to decide if they are for you.

I would be careful with people's recommendations to add more sound panels.  You can experiment if you want, but you already have corner traps and some side wall panels.  There is a fine line with panels that can push the room into the "too dead" sound and then the high frequency excitement is lost.