I just ordered a Denon AVR-X3500H from Amazon. They are an authorized dealer, so you get full warranty (I did not know that). This is a 2018 model, and it's the lowest level Denon with audio pre-outs and supports 4K. Roughly half off the regular price right now. Only 7.2 though.
It's going to replace my incredibly reliable Denon 3808 I use in the family room. I need to replace it because I've moved to 4K. Due to this move to 4K, connecting devices and running cables has become a PITA with the 3808 in the chain. I can't use it as a hub anymore.
I've had great luck with Denon. I regret not getting a Denon for my Theater room instead of the Anthem 1120 I bought. I love ARC, but the Anthem is clunky in comparison to Denon's user interface and system set up functions.
At any rate, it's worth a look. Might fit your needs.
Sounds like you're in the same boat as i am. Moving to 4k and the old AVR is obsolete (no HDMI plugins as one major factor). The Onk has worked great for 15 years. I do recall reading about problems with Onk HDMI boards but that was years ago. Aside from that, i'm not married to any brand necessarily. They are all pretty good quality, similar all around for the most part.