NAS and/or Cloud Drive

My current computer is now at end of life, Apple Mini. I am looking for the best option for a shared drive for 2 people mostly to save and retrieve documents, maybe some editing pdf, word, excel documents. Also minor editing images and videos. It is preferred to be in my local network, safe and ability to backup the shared drive. Also, I know I may be asking too much but an option to access online but need privacy because some data has SS#, application, etc.