I can’t say there are many products I could recommond but after using a Fingbox myself I can honestly say it’s the most interesting thing you never realised you wanted. It shows when devices like computers & phones connect or leave your network, it alerts you if a new device gets on your wi-fi and allows you to block internet access to certain devices or groups of them belonging to a person, say if you set a curfew for kids. Among other things it also keeps a log of internet outages which can be very helpful if you have a complaint with your broadband provider. Learn more & buy here: https://www.fing.com/products
Backing up any computer, whether it’s for home use or business is the most important thing you can do. Buying an external hard drive and using it as a Time Machine backup drive is so simple and makes such a difference if your internal hard drive or SSD fails in the future: https://support.apple.com/en-gb/HT201250