Replacement for Marantz AV8801: another prepro or receiver?

I went from an Anthem D2v to the AV8805 and find it much easier to navigate as well in 2 Channel much less sterile than the anthem. I am only using it for 5.1 but maybe sometime I may try Atmos but not in the budget anytime soon.

Look at the Integra DRX Line.  I went from the Marantz to Integra.  PLenty of power and all in one unit.

I will keep using the Parasound A21+ for the 801s -- it's a fantastic combination that sounds great, whether it's playing softly or rattling the dishes  The Parasound made an amazing difference over my 30 year old Nakamichi PA7 amp, keeping everything in the music mix crystal-clear even at high volumes without any congestion.  My lovely wife no longer complains when it's up loud.  But this is something I don't want to lose by going to a lesser preamp in the preprocessor. 

This mix is 80/20 movies/music with music streamed mostly from AmazonHD or my ripped CD collection from FLAC.  I don't play records very often (mine are all very old and scratchy), but still need a phono section.  But music is on quite a bit while I'm doing other things in the house, and Alexa/HEOS with AmazonHD music would be a welcome improvement, especially if everything can be turned on with a voice command rather than using 3 remotes (the Nak has no 12V trigger). I know both Marantz and Denon do this well.  And I've seen comments online that the analog section in these AVRs is really pretty good. 

So, after a whole lot of forum perusing, I'm now tilting towards the Denon AVR-X6700H (140wpc x 11) -- the price is right and it wold be great if I could use it to biamp the HTM71S2 center (not clear if that's possible but not a deal-killer as the center is not really used for music).  That leaves 9 channels for the surrounds -- 2 sides, 2 rears, plus maybe 4 smaller speakers in the ceiling for Atmos, none of which should tax 140wpc (I know it's less if all channels are driven). There is also the higher-end X8500H or the ridiculously priced A110 but those are both 2017 or maybe 2018 designs (8K support was added to the A110 and). I think I've learned that lesson -- get the latest prepro possible and only expect it to last 6 years. Bummer, but it is what it is. 

And I've seen comments online that the analog section in these AVRs is really pretty good.

Well, pretty sure you didn’t read those comments here.  IMO you have a good amp and speakers, and it’d be a shame to hobble them for 2-channel listening with the crappy preamp section of an AVR (unless you really don’t listen critically).  I think taking advantage of an AVR for the processing and amps for the other channels makes a lot of sense, but I’d recommend investing in a good stereo preamp with a HT bypass to handle stereo listening as it’ll greatly your improve performance there.  Preamps matter — A LOT!  Just my $0.02, and best of luck. 

It doesn’t appear as though the OP gave Anthem much consideration.  The Room Correction is definitely a plus, particularly 2 channel listening.  Why would you go back to Marantz after the bad experience you had?  Even if their products were more reliable Anthem is superior quality.  I haven’t bought any Denon gear for a while but since they merged with Marantz I have heard that it’s the same stuff, different logo