I might get flack for suggesting this, but for what you want, you'll not only need storage, but something to auto save the videos and pictures from your phone - and maybe auto delete old ones that have already synced to cloud when you are running low on space.

Amazon Photos does this. It has apps for iOS and Android that auto upload the photos. You can get a pretty large amount of storage for $99 a year. It's a "set it and forget it" solution for family photos and videos. It also has a bulk uploader tool for Windows to do the initial upload of your current photo/video storage.