Improve sound

For that budget I’d upgrade the DAC, and for God’s sake lose the optical digital connection. Get these two things and I think you’ll realize a notable improvement.
https://www.amazon.com/dp/B096S6HBQY/ref=syn_sd_onsite_desktop_30?ie=UTF8&psc=1&pd_rd_plhdr=t

https://www.usaudiomart.com/details/649932466-acoustic-zen-mc2-digital-coax-cable-1m/

Here’s a review of the Draco DAC that, as it turns out, is pretty comparable to my $1100 Musician Pegasus DAC that is, in turn, pretty comparable to the Denafrips Pontus ll. DO NOT underestimate the role of the digital cable because it makes a huge difference.
https://soundnews.net/sources/dacs/musician-audio-draco-r-2r-ladder-dac-review/

My advice, your next move, if 2-channel audio is important, is to invest in a good stereo integrated amp that’ll obliterate your AVR.  Use the front L/R preouts from the Anthem into a good stereo integrated and it’ll be a HUGE improvement.  AVR amps and preamp sections by and large suck as they’re designed to cram as many features into a box at a palatable price point.  The first casualty — power supplies.  Why?  Because they’re one of the most expensive components in good audio equipment and not even Anthem can include quality power supplies and keep their AVRs cost competitive.  So, my advice, do the DAC now and if 2-channel is important your next upgrade fer sure should be adding a good stereo integrated into your setup. 
Anyway, hope this helps, and best of luck.

I think you pose a good question. No question there are lots of possible answers. My thinking is you first want rock solid basic electronics… the preamp / amp. This will give you solid - detailed and realistic output from whatever your source is and what ever your speakers are. I think the Parasound would be a very substantial upgrade and take hold of the speakers downstream and get the most out if what is coming from upstream.

Typically, the best way to upgrade is to look for weaknesses and bring them up to the level of the rest of your system… then once you have achieved parody of all your components, enjoy for a long time. Then reach for the next level… never invest less than 2 times in a component upgrade.

So, looking at your system… first amp, then preamp… getting the Anthem out of your system. When you have a higher level preamp and amp… then start thinking about what should be next.

DAC first. The Bluesound Node 130 is not a  limiting factor as a streamer, but the internal DAC is. A Denafrips Ares 12th anniversary and the Musician Pegasus are both about $1,000 and are much better than their price might indicate

I have a pair of martin logan 40i. Blusound node most recent version. Anthem mrx 720. I have the speakers connected with bi wire blue jeans speaker cable. The blu sound via optical cable.  I have about 1000 dollars.  What could I upgrade.  Thought about getting an amp like the parasound 23+ or upgrading the streamer to a cambridge. Please I would love some help/suggestions

There are about 100 ways to go.

• simplicity: TDAI 1120 (but that breaks the $1000 budget)
• active speakers and get rid of the cables and amps (also breaks the $1k budget)

Personally I would save the $1k and give it some thought as to the outcome.
Saying one wants “better”, sort of demands some idea of what better is, so we can go about getting towards what better is.

What is it that you do not about it like currently?
How is the current system less than ideal?
Which of your system components do you feel are keepers?

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.