Take a look at the Sony MTF lens resolution charts over at Lens Rentals
https://www.lensrentals.com/blog/2019/04/just-mtf-charts-sony-fe-mount-prime-lenses/
I find the blog posts on that site really good reading and they can be trusted. They are not affiliated to any manufacturer, they process a lot of gear through their rental system which all receive a lot abuse and the reviews & testing is averaged out across ~10 off the shelf production units.
In terms of the 90mm Macro lens - It's an average lens in that range.
Compared to the sony 135mm F1.8 : The 50 lines per millimeter (lp/mm) purple line is a lot lower than the 135mm [ both wide open: F2.8 vs F1.8].
In fact the 135mm tested at 50 lp/mm out performs the 90mm tested at 30 lp/mm, and it's over 1 stop faster. I have the Canon Macro L IS F2.8 lens and that performs better than the Sony 90mm Macro.
/Geek mode