My experience is 99% outdoors:
I have been buying the ones from Aldi when they come up.
Otherwise the blue ones from Supercheap when they are on special.
Went to Autobarn for one for the Crown a few months ago. Ended up being cheaper to buy an indoor cover and an outdoor cover than one “indoor/outdoor cover”.
Seems to be working well for the car in the carport.
Cheapies from ebay were complete garbage and self destructed in about a fortnight.
Even if you do the straps up tight, they last much better if you weigh the cover down. I use old motorcycle tyres for their combination of weight, cost and lack of sharp edges/hard points.