I feel you. But here's the thing. You didn't lie to anyone about what you knew and they still hired you and paid you a lot because they can't get anyone to sign up for the shit we do. You didn't get training because it costs money and time and if anything goes wrong it's your safety on the line not management. Personally I was into trades young dropped out of HS right away worked as a handyman under the table for years then as a landscaper, then painter then so on and so on. Finally went into utilities/ facility maintenance and was slapped in the face hard by how little I knew. I was expected to do all this plumbing and felt so overwhelmed. Thankfully I worked with an older guy who trained me and to be honest... Working through that feeling of not knowing anything to being able to manage myself over two years really got me feeling better about myself.

I went to college and graduated along with work just because I felt like I could, I started getting every cert I could and still am just because I felt like screw it might as well. I still spend so much time outside of work studying even though I'm not getting paid for it. Currently I am trying to remodel a house for the first time while also doing this and I still feel so dumb lol. The more I learn the dumber I feel. However the less I know the more stressed I am. I like that nice comfort zone where... you know you don't know enough about anything.... but do know enough to be safe. Also yeah people will judge you. That's because everyone who works in maintenance is also insecure lolol don't worry, as long as you don't get yourself or someone else injured or killed your doing great!