Upgrade path question with $2k to spend

If your system is 2.1 or 2.0 it has no business incorporating an AV receiver...preriod(s).  I fully support blended systems using an AV receiver for center and surrounds, with a good dedicated integrated amp in HT Bypass mode for the main speakers, with music-first sources connected directly to the IA, and HDMI-only devices to the AVR.  But in your case you have no other speakers, so sell the AVR and spend $3K on an integrated.  Options abound.  Halo HINT, Black Ice F35, used Hegel, Naim, Rega...etc.

Please excuse my question as a newbie. I assume that the Yamaha Aventage RX-2070 (amp) also handles quad Blu-ray.  I am in the same situation. If the amp is replaced with a dedicated two-channel, how would access to the quadraphonic sound of those music Blu-rays, which seem to be proliferating (Chicago, Pink Floyd, Beatles, etc.), be accessed?  Thank you for your consideration.

I have 7.1 so I'll be keeping the Yammy for HT.  I'm thinking of external amp with HT bypass being fed by a miniDSP so I can get Dirac Live (I need major correction in my room and can't treat it)

Was seeing good things about the Peachtree

@davedword short answer is if you replace your AVR with 2-channel, you can only play back 2 channels (L-R stereo) of a multi-channel recording.  Consider though that most multi-channel audio releases also include 2-channel stereo.  Frankly, most of the re-channeling of old releases isn't all that great (unless we're talking Pink Floyd), and you'll get more enjoyment out of a great 2-channel system with millions of available recordings than mediocre multi-channel with only a limited amount of available source material.