FWIW, I shoot the WWL-1 with the Sony kit lens (16-50 mm for the a6500) and it works pretty well. It is really nice having the ability to zoom through with the WWL-1. I am considering upgrading to the a7R IV (is that what you have now @stuartv ?), but I won't have enough saved up for the Nauticam housing for awhile, so it'll just be used dry. Maybe I just need to sell my Nauticam a6500 housing first?
Yes, I have the a7r4. But, I have barely gotten to use it in the water yet.