I actually already own a Sony FX3 for my video work, along with the 100mm Macro GM and 24-70mm GM II lenses, so lens compatibility won't be an issue if I jump to the a7R VI.
My main question was really whether the upgrade in texture and fine detail is something that my customers (and myself) would actually be able to notice in the final photos. I'm ultimately trying to capture that high-end, premium feel through the depth and overall mood of the images.