Don't use duct tape, that only makes things worse. Things to try are the blister pads by spenco they seem to stick better than the others, tegaderm, hikegoo, a light hiker wool sock, and these
RUN 2.0 Lightweight No-Show - Wool - RUN - Shop I have found wool is softer than synthetic and thus doesn't blister as soon. I get blisters just thinking about it and using the combination of hikegoo, light hiker wool sock, and those injinji socks I haven't gotten a blister in awhile. I just did a 12 mile ruck with 55 lbs and no blisters at all. The hikegoo is the shit!!
https://www.footkinetics.com/products/hikegoo-regular-2/