Appropriate Power for 1.7i's

I am sure this is the type of question that gets asked a lot, so I beg your indulgence for one more:

I have recently upgraded my speakers to a pair of Magnepan 1.7i's.  I am enjoying these speakers even though I know they are not receiving an optimal signal.  My goal is to provide a better signal.
 
My primary source is TIDAL HiFi, and here is my current setup

Power:  Yamaha HTR-5450 (only front channels used).  Ostensibly 85 w/channel --- I am aware that the specs for home theater receivers tend to be -ah optimistic.

DAC:  ifi nano iDSD (burr-brown)

Digital signal provided by PC

My budget for upgrading the Yamaha is modest:  $700-$900

Here is my want list:

100+ w/channel Stereo into 4 ohms.  ( I have no need for more channels):  Preferably Class A/B  (as opposed to D)

I am not opposed to purchasing used, in spite of the additional effort involved.

I am considering the Denon Heos and  Sonos Connect as a preamp.  I am not opposed to an integrated amp, but I like the fact that these units allow me to control my selection via a phone app (my phone is an LGv20 w/ Android 7).  Since I tend to listen to albums rather than individual songs or even playlists, the lack of this convenience is not a deal killer for me.