The Synology system is nice and works with a very wide variety of cameras. We have found the HikVision cameras and they have plenty of supported models listed on their page here Surveillance Station IP Camera Support List | Synology Inc.
I do have a video reviewing the Synology Surveillance station platform
NAS Choice and sizing are very dependent on the your video retention needs and they offer a NAS selector tool here NAS Selector | Synology Inc.