What is it you expect to hear from hifi gear that you have not yet?

One thing for me is a noticeable difference in streamers. I need to work on that.
But I’m not really interested in mega buck audio servers.  What about just a streamer?
I am still mostly using Squeezebox Touch as my streamer with Ipeng controller app on Iphone. Wonderful device still, still sounds great and lots of functionality especially with add-ons to Logitech Media Server. DAC has also been mhdt Constantine (SS, NOS) for a number of years now.

I also run Plex and use Plexamp app on my Iphone mostly with headphones (via headphone amp) and Carplay in the car. Plexamp is relative new and delivers very good sound quality.

But am always looking to move on to latest and greatest. Just not sure what that would be and how it would be worth it for me when what I have sounds so dern good and provides so much flexibility.

I’ve heard newer streamers at dealers and shows, have not seen or heard anything yet that makes me want to jump.

How do you know what quality of the stream is, or of the original source of the digital stream?
I look for two things in a music reproductions system:
1. I want piano music to sound like it is coming from a real piano playing in the room no matter where I am in the room.
2. I want to be in the next room and have the music trick my mind into believing there is a live performance happening in the adjacent room.

I have occasionally heard systems where the sound was coming from another room and I wasn't sure whether it was live or recorded and that is an ultimate system to me.

There are probably some systems that can do it or come close but most are not really audiophile systems.  I should have added a third item and that is for orchestras to produce the weight and feel they do in a live performance from the system.

One of the problems in achieving these goals is that recording engineers either do a poor job of recording or the way they mix it destroys the information needed to fool the ears/brain.  The focus recording engineers have on keeping all of the audio coming from the center/center channel means they have turned a stereo signal into a mono signal.  There was a time when they did binaural recordings and I recall the excellent recordings that the owner of an audiophile store in Miami did of the New World Symphony with two mics suspended on cables in the venue and those recording were just incredible.  Most of the recording done today are horrible with the engineer/producer panning and moving instruments all over the place when they are in fact stationary during a performance.