The OP is looking for an outdoor cover.. no use pointing him to a thread where everyone puts their car in a garage.
OP, i have used Stormforce covers on my e85 previously for 5 winters, no issues with them marking the paintwork they a 5 layer cover with a soft underside.. waterproof and breathable too so no damp under there.. downside is they are a bit pricey at 170 odd quid but they do do the job and are well made.
https://www.stormcarcovers.co.uk/collections/bmw/products/monsoon-car-covers-for-bmw?variant=974490064