Improve sound

I'm (sort of) with @holmz . For $1k, I think you can make some sonic changes by replacing something, but it may be the sort of thing you like at first but then later realize it doesn't really allow you to enjoy the system more.

You did not mention your room.  I would think real hard about the room, speaker placement, setup, etc. and fiddle with that.  You may find the need to spend some or most of that budget on some treatments or other things relating to the setup, and if there is improvement to be made in terms of setup, it will vastly outstrip what you can achieve by dropping $1k on equipment given what you already have.

Yeah - the streamer, DAC and amp, sort equals a TDAI 1120… and that also tackles some of the room issues, but indirectly so.

But so does active speakers.

It is easy to become emotionally attached to speakers… and base a system around them.

At some point we need to use some objective reality to determine if the speakers are worth keeping, or are the long pole in the tent.
(I do not know much about those ML speakers, and am speaking of my system here.)

I think your DAC is fine, the least problematic. Your amp is OK, but does it work with your speakers? Start with a small change, bookshelf speakers. Look for music that you love and listen and look for sounds that blow your mind and make you want to turn up the music. You need a baseline, something to strive for and it seems you have been feeling "meh". 

I know nothing about your amp but it's safe to say, it's for home theater/entertainment and not for peak audiophile joy. 

The short version is: you have to learn about yourself. Neither your speakers nor your amp is audiophile, maybe midfi, if you sell both and add $500 you will have a lot of options ($2500?)

You can get a Parasound 23+ ( assuming used) for a $1,000?

Upgrade the room first. There's always something you can do to improve the room. It plays the biggest roll in the system's sound signature.

Many here know this but really hit a wall (pun intended) and never fully exploit the room's potential, myself included.

I learned by sheer accident after years of believing I had done enough. 

Room treatement is the most important upgrade for electorstatic speakers. Since I have owned ML  -> Quad -> Stax -> Sound Lab A645, I think that I have some experience with this subject.