Some of this - like less saturated colors - sounds like possibly settings related issues like HDR. Barry, do you know if the firmware on the Oppos was ever updated? HDR10+ and other HDR updates were added after 2018. There is also an HDR indicator logo on the front panel. Might be worth a quick test to check if you see that light up on a 4K UHD disc.I bought the Panny 820 back in 2018. (It replaced an Oppo 203, only b/c at that point Oppo had discontinued it, prices were up and I figured I could sell it and not worry about future support.) So the 820 is pretty old, nearly the same age as those Oppos. I ended up selling the 820 b/c I wanted something that would support at least multichannel SACD for my surround system. So I sold the 820, and grabbed a Sony UBP-X800M2. I rarely use it, to be honest - maybe once a month for a movie I really want to see on disc instead of whatever streaming. I'm on the cusp on starting my long planned project to rip my BD collection, which will mean it gets used only for SACD playback, probably 1-2 times a year.