I guess now that only bio-fuels are available at the pumps and E5 being the least bio available, there is not much in the way of choice. I have zero experience of bio fuel issues as yet.. fortunately. Just thought to post the link below in the off chance it might assist in advancing knowledge..?

https://www.porsche.com/uk/accessoriesandservice/classic/genuineparts/producthighlights/additive/