This was me last year, coming from a7III. I went A7RV mainly due to pricing. The price difference on camera and housing adds up to a pretty penny. However with a comfortable budget I would probably go with the A1. But it prob depends on your needs, advantages of a1
- Better video specs
- Higher native flash sync speeds (does this still matter with high speed sync?)
- Marginally better autofocus
Big draw for me of the a7rv, over the a1 other than price, is the 24Mpix files when shooting in APSC mode.
Something else to consider is that sony might come with an a1II in the not too distant future. A1 is now 4 years old