Is my DAC my weakest link?

+1 @erik_squires on the Furman recommendation for your system. A power conditioner basically does what it sounds like it does. It makes sure the power your system sees is, in easy terms, "clean and steady." The electricity coming into your house has audible noise in it and it doesn't always (or ever) come through the lines in a uniform, steady flow--electricity surges--and a power conditioner helps harness this attribute and provide your equipment with a steady diet of cleaner and steadier power. I've oversimplified but hopefully the explanation helps you. BTW there are many folks on this site who don't use any power conditioning because they do not think it adds significant value. I have run previous systems without power conditioning. However, I am now a strong proponent of using power conditioning. FWIW the Chord Mojo will probably provide you a more discernible audible improvement in your sound than an entry level Furman. But that doesn't mean the Furman isn't a good idea for you. 

There is nothing wrong with the AC power coming out of your outlets! Don't fall for all this "power conditioner" B.S. Same for interconnects! Use what you have and enjoy the music! There is NO benefit to raising speaker wire off the floor! Enjoy your system and don't become a neurotic and gullible audiophile!

Concentrate on source and output (speakers). You got fine speakers. A bluesound node2i will give you good streaming and dac with subbass output if (when) you need more in the lows. Make it simple. Try to find out what sound you like. Move the speakers around in the room. Don't take your time and wallet comparing cables. Have fun!

I have a Marantz SA-10A CD player and DAC. It is as good as any source I have including Vinyl. CDs are superior to almost streaming service when played on top rate equipment. 

Since you are streaming Tidal Hi-FI through Audirvana I would recommend a DAC that can handle MQA. The Mytek Brooklyn is probably the best overall (for the price) but if you just want to get your feet wet you could try an Audioquest Dragonfly Red or Meridian Explorer2 DAC and either return them or keep one for travel or a smaller system (I have the Explorer2 hooked to a MacBook Air and powered speakers in a secondary office). 

If you like the sound but want to move up you could try the Project Pre Box S2 Digital or the new NAD C658.