I also have this lens and I have been using it far more than I thought I would. It makes up part of my kit.

For me, the major advantage of the a7siii is 4K 120p. A relaxing snowstorm:

Firmware version 2.00

• Adds the P11:S-Cinetone picture profile preset.
  S-Cinetone is a new video look that introduces a color matrix that produces highly regarded skin tones.
• Adds support for setting Steady Shot to Active during recording movie with S&Q Frame Rate
  The Active setting cannot be selected if the S&Q Frame Rate is set to 120fps/100fps or higher.
• Improves the overall stability of the camera

https://www.sony.co.uk/electronics/support/e-mount-body-ilce-7-series/ilce-7sm3

S-Cinetone 4K Video (with plenty of faces):

Due to production reasons, it may take some time before the product is delivered for the digital single-lens camera “α7S III”.

We are currently making every effort to meet the needs of our customers, so please wait for a while.

We deeply apologize for any inconvenience caused

Camera is out of stock in many stores.

On camera sensor

The CIS part number is IMX510AQL in a 294-pin LGA ceramic package.

It turns out this sensor was a 2×2 binning design. This means IMX510 actually has a 48MP native resolution. The RGGB Bayer pattern is spread across a 4×4 grid. After sensor readout, the four pixels in each pf the same color are then combined digitally to give one pixel before sending out on the SLVS-EC interface.

https://landingfield.wordpress.com/2021/09/03/sony-a7s-iii-has-a-2x2-pixel-binning-imx510-bsi-sensor/

The camera will be in Stock again in more than two months from now at B&H.