Places to shop for clothes online with size accurate models/tools? (women)

Hello, I buy a lot of my clothes online and I  am tired of buying clothes only to find they don’t fit as I thought they would. I would love to find some sites that offer any of the following: a video/picture someone modeling the actual product on that page. There is a feature called “catwalk” on simplybeach.com that is a good example. A way to see someone in a size at least close to mine modeling anything from the store, to see if things run small/large etc. Anything with the models size reported would be helpful to a degree  Most places only have perfectly proportioned girls modeling and I just seem to keep getting burned, I mean I know my sizes and such things just don’t fit like I expect them to. I am a size 34dd which is where most of my issues happen. Specifically I am looking for swimwear but any type of clothing store like this is helpful. Thank you!!!