I'm using a self signed CA for my home network with caddy. You just set it up to use a ca once and afterwards it just works. So yeah, really easy.
Iirc you can upload your own certificates and keys in npm, you'll just have to manage the CA manually or with some other tool.
People in red Teams are white hats. The terms describe different things. The "color wheel" is operational and thinks in the context of an organization. Red Team tries to attack our stuff, blue team tries to defend our stuff, yellow team builds our stuff etc.
White hat is just a term for ethical hackers, black hat is a term for criminals. Grey hat means someone in-between (think political hacker defacing website of organization they don't like), there is also some more but the shades of grey are most important.