One more thing - install Wireshark and get a real-time view of what your network is doing. Massively helpful tool.

For homelab, start with the absolute basics - setup a firewall, and make sure you understand how it works! Map out your network topology, even if it is just your DSL box, router & your PC + printer with a raspberry pi (or 2) for your project.

After you’ve made absolutely sure that the outside world can only get in where you’ve let it, then you can focus on having good application-level security; unfortunately this is really case-by-case.

As for resources, I would start with YouTube - you tend to get to focus your learning a bit better and spend less time searching for something relevant (as you mentioned, enterprise tends to be the focus, because they’re often the main targets of network related attacks). For more depth, but not crazy detail, try the O’Reilly books or similar on networks & related security topics (there are a few!)

I bought so many microfiber cloths that when one gets too dirty, it goes to workshop duty and I get a new one for glasses.

For cleaning lenses properly (which I do once a week or so), I tend to use lint-free tissue (Kimwipes) and a mixture of 85% petroleum ether & 15% pure isopropanol; both of which should be available at your local hardware store. Bonus is that this is also appropriate for scientific optics, like microscope/camera lenses & instrumentation components (mirrors, prisms etcs) - just don’t rub them!