You could just buy one of the current easy to use systems. Lots of features, including wireless cams, lots of motion sesitivity and area parameters as well as online storage. And you can see them all from your phone, some can also have pop-ups on your TV when someone. comes to door etc. I use an Arlo system. These systems have their own embedded server dedicated and secured for single purpose (hub) that all the cameras connect to and allows you access. They are more like an appliance, so easy to use.
I am old too, worked in the IT field for 20+ years at a major university. With these new video systems already made, feature rich, more secure than you can make and keep some open source web server secure this is the way to go. I have had my system for 2 years and I am very happy with its picture quality, ease of use, reliability and feature set. When you buy one you get a certain amount of storage which has proven adequate for me and there is no monthly charge.