Been a while...
I sold my Canon kit and got the A7R IV, plus the Sony 16-35mm f/2.8 GM. Since then I added the Sony/Zeiss 50mm f/1.4.
Favorite shot so far with the 16-35:
https://www.flickr.com/photos/43656904@N06/49224261062/in/dateposted/
Took this at Longwood Gardens during their Christmas event thing.
I've mostly just done some testing with the Sony/Zeiss 50mm, but I liked this pattern on a local house, so I snapped this:
https://www.flickr.com/photos/43656904@N06/49293236053/in/dateposted/
So far I've been enjoying the Sony. Some things are definitely a bit different (menus suck). There are plenty of custom buttons, which is a nice feature. The ergonomics are quite good.
I have to say that doubling resolution does introduce some things. The camera's internal hardware could probably use a little bit of a kick in the ass - reviewing photos (zooming etc.) can be a little laggy, and that's with one of the new Sony Tough cards. On the other hand, it might not be bad at all, considering how my desktop or laptop handle zooming etc. The big thing to consider is that, even with IBIS, you have to be very mindful of shutter speed and camera shake. 60MP will reveal every flaw in your technique. No mercy.
I quite like your portraits you've been posting. Great subject choice definitely factors in :)