My primary blade is “Feather” - considered THE sharpest from a Japanese medical blade company.
That said, I also rotate in Perma-Sharp - just a hair less sharp, only 9-cents a blade and very, very close to Feather
https://www.amazon.com/dp/B009BS5CUA?psc=1&ref=ppx_yo2ov_dt_b_product_details
I find that Feather is overkill. It didn’t shave better for me than any other blade but it cost more. Israeli Personna’s were good. $15 for a 100.