Correct deck stripper

I'm attempting to refinish a deck. The previous owner used either paint or a semi-transparent stain. I've tried the brands of deck stripper bought at the big box stores (Behr & the one from Lowes). I followed directions as well as variations (longer sitting time, thicker coating, etc.) and neither one pulled up the paint but just pulled of the "dirt" on the stain/paint. I'm wondering if there is a brand that is stronger that would work? If it was paint they used, do i need to use another product?

The paint is flaking off and I'm wondering if I can't get a stripper to work are my options to sand it off? Paint over it with another stain/paint (maybe one of these deck toppers) or start over and rebuild it?

Thanks,