Sony A73 is more than needed for 35mm, but 6x6+ is different story - for that I think A7R3 or R4 is better. (But I don’t have measured results to comment on that to loudly).
Sony A73 resolves around 3500dpi with Sony 50mm F2.8 Macro, tested to Golden Thread solutions.
Hopefully soon I can get my hands on for Sony A7R4 for testing also.
http://www.imagescienceassociates.com/mm5/merchant.mvc?Screen=PRODUCTS&Store_Code=ISA001