If you want 100% control and keep everything local FrigateNVR and the POE cameras of your choice. You can find used hardware online and pick and choose where you want to spend more cash. To save space for recordings a gpu or tpu/npu can be used for object detection.
https://lemmy.world/c/selfhosted is a good place to search for some information and help.
Make a syncthing directory for each person you want to share with. For only a few people it’s really simple. I do this with a few different things. Each “share” can be setup with individuals or groups as you need.