Inventing substances or devices that violate the laws of physics is no problem as long as I am a suitably nerdy, pale and/or obese man. The thicker my glasses, the easier the inventing will be.
I can get all the books, PhD theses, and other materials I need for a scientific education that makes me an expert in a field of less than a hundred world-renowned scientists without anybody noticing or asking questions with the possible exceptions of- Mom, whose basement I live in. My landlord who complains about the noise. The old guy whose stand I buy my dailly paper from and who always makes some dumb science joke.
I can build my invisibility, teleportation, time travel, death ray, fighting robot, Iron Man style armor, or other device out of easily and cheaply obtained materials and parts. Nobody will notice the huge device in my living room, until Mom or the landlord walk in just as I strap myself in and press the button.
In some cases, the final crucial piece or the substance needed for a power source can only be obtained through theft of a museum, university, or military base. Fortunately, one of my side projects has produced robots, mind control devices, or genetically engineered creatures which can be used to steal this final part.
Joining STAR labs, AIM or any similar organization of brilliant scientists will result in either-an untimely death, defeat by a super hero and a long stay in prison, accidental mutation into a hideous monster with subsequent career as a supervillain, my colleagues using me as a test subect which will result in the above transformation.
If I use any one invention for a period of several years, it will have an unforseen side effect on me. This will be negative, and possibly fatal, if I have become a supervillain and am in good health, or wealthy. It will be positive if I have become a supervillain and have just been through something that would kill a normal human. If I have become a superhero, the effect will almost certainly be positive. If it is not, it can be reversed after a short but intense quest.