It's all what you want for video. I have a Denon AVR-2312ci that I was using for my 3D 1080p TV 5.1 system.
I got rid of the AVR-2312ci from my 4K main 7.1 system because I disliked the inconvenience of needing to switch everything through the TV's own HDMI inputs (to use 4K), then send the TV's Optical output for DD 5.1 to my AVR-2312ci.
I did buy a Sony X700 UHD Bluray player that had a separate audio only HDMI just to go to the receiver so it wouldn't downmix my 4K video signals to 1080P. So the only way I got better than the standard DD 5.1, was to use the X700 Bluray player. It had terrible streaming app offerings and it just can't replace a Roku or Chromecast w/Google Tv streamer.
I hated using the TV as a video switch and audio feed as I couldn't monitor anything from the Denon as I was 12' away and it had a very thorough display screen and still couldn't read it. Even then, many things were only available on the on-screen display.
I finally updated my receiver to a Denon AVR-S960H and what a difference. Now I had discrete 7.1 channels from Atmos from the video streamers and even when Atmos wasn't available, I got DD+ 7.1 on some movies. Big improvement over DD 5.1! I bought that Denon AVR-S960H back in '22 for $600 even from Amazon. if it weren't for a stupid Nintendo Switch Dock design that makes static popping noise on receiver turn on, I would still be using the Denon AVR-S960H on my main system.
Since I thought the problem was the receiver, I sent it in. Found out after, through a couple other receivers, it wasn't the receiver. However Denon warranty repair tech had an attitude and wouldn't even discuss the issue before I even sent it in. So it went in, to later find out, it wasn't the problem. He said he replaced some power supply diodes but who knows. I got it back and it works flawlessly with some new minor scratches from the professional and careful repairman
. Luckily they are on the rear side where they can't be seen. This repairman also does warranty repairs on Yamaha and Onkyo, and others.
Anyhow, I did get another receiver as prices on receivers on Amazon where crazy cheap even before Amazon day. I tried an Onkyo receiver I didn't care for, so returned and found that Amazon themselves again, were selling the AVR-X2800H for $679 on Amazon day. I jumped on that deal as I was only finding it previously at around 1K cheapest from an authorized retailer. So I now have the AVR-X2800H in my main living room and the AVR-S960H in the Media room 5.1 system (although I may be able to expand to 5.1.2 with Atmos Front Height speakers
). Denon can thank that warranty repairman for a repair that wasn't needed with his lack of caring to speak to the customer ahead of time, then to the purchase of a AVR-X2800H due to the expectation that repairman wouldn't send the AVR-S960H back in one piece within the same year! He refused to tell me when he would be finished and sending it back. Delivery just appeared one day on my front porch, on a "RAINY DAY". Luckily I was there to take it!
Sorry for the Rant, but I guess I feel I still came out ahead with such a good deal on the X2800h.
Point of the post is, don't think a dedicated home theater receiver is going to work the best when you don't use it as the main video switcher. if you plan on using 4K or 8K video, get a new receiver! Also pay an inexpensive price so that if you want to upgrade to the latest video format, you can afford to do it without regretting the price you paid on the current receiver. One of the reasons, I don't want to pay over $1000 on a receiver.
If you like Onkyo, the TX-NR6100 is still really cheap on Amazon but it has no pre-amp outputs. Also it's been said at ASR that Zone 2 preamp outputs on all makes, aren't the highest quality as the main zone is. Some said inferior DACs.
If you want to use external amps as you said, the Onkyo TX-RZ50 was right at $1,000 from Amazon themselves. BUT beware, Onkyo now forces (with a 7.1 speaker setup, using a 5.1 signal output) the surround channels to play out of the back surround speakers, and the leave the surround speakers silent. This is by design that only Onkyo themselves know why, but I couldn't live with it.
Also a better option maybe, as I have never used this receiver, the Yamaha RX-A4A seems very high end and has preamp outputs, 110 watts/channel and is a 7.1 channel receiver. It's MSRP is $1299 but you may find it cheaper. Being this is a lower price MSRP for what Yamaha is claiming with this receiver, I have never seen it's price go much below MSRP.
Good luck in whatever you decide.