Camera decision assist: A9 or A7r IV

Hello all,

I would like to ask a question and to know your opinion on a decision I have to make regarding my next camera.

I am currently using an A7 III with a broad set of lenses (incl. some modern CV manual lenses). The main focus of my photography is street and urban photography, especially candid photography and low light street photography with moving subjects. Feel free to visit my stream on flickr (link below) to have an idea about that. I don't care for any video functions and don't like flip screens (therefore the A7 IV is not an option).

I have been really happy with the A7 III and have used in for just under 3 years now. I have only three issues that are really annoying for me:

1. Distortion with moving subjects when using the electronic shutter.

2. Horizontal stripes when using the electronic shutter under artificial light.

3. Autofucus sometimes unreliable (e.g. when in low light, shooting against the light, shooting with eye af when more than one person is in the frame, shooting in light rain).

My main "problem" is actually the AF performance and the stripes under artificial light. I know that the scenarios described above are challenging for any AF system. Still, I would prefer to minimize these annoyances.

From what I have read and see on specs sheets the Sony A9 (MK II is too expensive) would fulfill all my requirements. The thing with the A9 is that the camera is still relatively expensive and the used ones make an impression that they have been really used extensively. Therefore, I also consider the A7r IV to be a good option. The AF has been updated compared to my current A7 III and the shutter is quieter than the one in the A7 III.  I could use sometimes the mechanical shutter in situations where I currently use the electronic one. The high resolution viewfinder/screen would help me also with MF when using my CV lenses. On the grey market (or used in perfect condition) A7r IV can be found for a slightly lower price than a used A9 in really good condition. Additionally, the A7r IV is a newer camera with some other updates (e.g. body design).

I have read many online reviews and from what I understand the A9 still has a better AF than the A7r IV (and of course no issues when using the electronic shutter).

What would be your recommendation in my situation for my types of photography? Am I missing important aspects?

Thank you for taking the time to read this long post
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http://www.flickr.com/photos/graveur/