Congrats on your current system. Before you pay for upgrades there are some freebees that are very important. I have an Anthem preamp with ARC, when you run it you get a nice graph (which you can see in my profile). If you could post your ARC results that is a good place to begin. As far as streamers I use both a Paradigm Link and a Martin Logan Unison, both Anthem companies. You paid about $3K more than the AVM70 because the 90 has better DAC’s in it. I don’t know that buying a new DAC will be as much as an upgrade than just being different. I would get the acoustics in your room super dialed in before spending more $. If you could post your system it will help, when I checked your profile the link is empty.
The ARC graph will look like this, yours will probably include charts for your subs and other speakers as well. If you need help posting it just reply: