AV Processor Conundrum

Old guy here, new to posting, but always been a audio nerd. I have a Marantz 7706 with 7 channel amp for family/kitchen area and in ceiling speakers -(WAF). I am assembling a  25% listening, 75% TV/movie room in my study - (WAF is not a factor).   In the study I currently have Parasound P7, A51 and A21 and OPPO 105.  Great sound but interconnect and handshake with HDMI is not great. Base management is week with the two SVS SB4000's subs.

I want to do it right and go big on sound and musicality, but as a penny pinching engineer I go quickly down the rabbit hole.  I had an ARCAM AVR long ago, but the issues with it always needing to go to the shop killed me. So no ARCAM for me - sorry.

Anthem AVM 70 or 90 worth it?

Get another Marantz 7706?

Is the Marantz 8805 that much better?  I am pushing 60, ears are not perfect either.

Krell Foundation used or used Bryston ?  They seem little antiquated.

Save the money get a marantz cinima 70 and use as a preamp and ugrade all the speakers?

I am leaning toward another 7706.  But love to read all your comments and opinions.  And no, I am not offended and love the humor too.