System assessment...

No regrets.  If you want to keep the amp, you can always add an upgraded external dac.  And if you’re like me, you may prefer vinyl as your primary source for serious listening anyway.  

Nice system, if you come to Chicago visit Quintessence Audio, great store with 3 rooms and systems in each room based on Hifi tiers, I also extend an invite to come hear my system , I’m in a Chicago suburb, also retired now 6 years. I’ve built my system on a synergy approach and have enjoyed it very much. Also maybe you could come to Axpona in April 2025, in Schaumburg, best way to see and hear many systems. Good luck on your search.

Congratulations on retirement.   I have reached 1 year  in retirement and I am enjoying myself while  waiting for my wife to retire shortly so we can travel the US and Europe.  You have a solid system with no glaring issues other than whether you have addressed power quality issues.  Good power conditioning will improve all areas SQ (timbre, background silence, dynamics, and staging/imaging).  My favorites are the Shunyata Denali or Everest, or Audience Adept Response T series.  Of course, the progression would be to separate lines.  Before you go on an endeavor to make improvements, attempt to critically analyze where your systems strengths and weaknesses are compared to your perception of live music. For example, do you believe your system is too analytical or not detailed enough; do believe it is true or false to timbre; do you think dynamics are weak; etc.  Then read pro reviews on equipment in your budget, compare that to pro reviews of your equipment and determine if the differences line with the improvements you wish to make.  Remember, pro reviews are guidance and you must audition.  Finally, go to a good retailer, explain your objectives and the research you have conducted asking for their assistance.  Try to negotiate a demo and return in your system to give you a chance to validate the improvements in you system and home.  

+1 for AXPONA. I went this year to hear a variety of speakers, and systems of course. It is a great way to get some perspective. I was able to rule out a lot of them, and put some on my wish list. 

DSP would be a good idea. At least get a view of what your curve looks like.  Modifying things along the curve could be a really good thing.

And then I'd buy a puppy