1st, congrats in the very sexy Yamaha A-S1200. So pretty looking.
Since you ditched your turntable and transferred your CDs to digital FLAC, it seems you fully embrace the digital FUTURE, which I do also.
As for me, I am more into convenient high-end like the Yamaha CX-A5200 AVP and Yamaha RX-A3080 AVR and simply stream all my music to Yamaha MusicCast.
And as for DACs, I have heard many high-end DACs, and I can’t tell any difference among any of them. So I don’t care about any external DACs.
For example, the RX-A3080 has the ESS SABRE PRO ES9026PRO DAC, which is 32bit 768kHz 124dB DSD. The Marantz HD DAC1 has the Cirrus Logic CS4398 DAC, which is 24bit 216kHz 120dB DSD. Technically the RX-A3080 has a better DAC. But I won’t hear any difference just from the DAC.
Also be aware that most Room Correction EQ will downsample your music files to 48kHz. I only say this because you mentioned about the external DAC.
But there is a different system for everyone.
At the end of the day, we have to be happy with our decisions.