As long as you don’t leave it in there for weeks or months it should be fine. I’ve been running 51-83% ethanol (E85) for the last nearly all 2 years and the beast is still ticking. it’s been throwing the catalyst inefficiency code a bit more when that’s in, but it’s also got 473,000 miles on the original engine too...
Geeze Louise sir — what the heck do you drive?