Sony a9

“Main advantage of an A7RV is the resolution - you’re going from 33mp on the A7IV to 61mp on the A7RV. That means more flexibility with cropping and more detail overall. It also means you’ll have a lot more data to deal with, both in terms of card space needed on the camera and hard drive space at home. That higher res sensor will push your lenses too - you won’t be able to realize all that extra detail in your photos if you have sub par glass. One other detail to consider is that the A7RV sensor is not very fast in terms of readout. Your prior A7IV sensor wasn’t great in this department either, but if you’ve been wanting to get into shooting animals or fast action, you might be better off with something in the A9 series. Those cameras though are purpose built for that specifically - you’d be getting a lower resolution sensor that instead reads out quickly leading to faster burst rates and less rolling shutter. Personally, unless you were feeling limited by the A7IV in some way, I’d just get another replacement of it. It’s the jack of all trades camera in the Sony lineup and all the other cameras in the Alpha series are designed to specialize in one specific thing, so unless you need more capability in a specific area, it sounds like your current model would do you just fine.”