Don’t be discouraged as there’s nothing wrong with you. Based on your ability to bounce back from adversity (as demonstrated by your stated ability to secure better and higher paying jobs) and your ability to clearly articulate your thoughts you seem to have the basic skill sets to develop a successful professional career, if you choose to do so. It’s an unfortunate reality that many employers use NDA/non competes as a weapon in the industry and many companies will fire a new employee when faced with potential legal action over these types of agreements.
Not sure which company is worse, the company that fired you over a trumped up charge and then sent you a cease-n-desist letter when you stated your new gig or the company that fired you after being threatened with legal action from your former employer?
Before I go any further I should say NDA/NCAs are legally enforced (or not) at the state level, so there are many factors affecting their enforceability including where the state in which you live, the state you are employed, which state you pay taxes to, where the company you previously worked for is HQ’d and where your most recent company you worked is HQ’d. Oh, and most importantly, what exactly your NDA/NCA agreement that you signed says exactly.
Without having all this information to review its hard to advise but I will take at face value that, as stated by an attorney you spoke to, the NCA you signed is “overly broad.” I also think it’s safe to say this NCA would not even apply to you since, as you say, you were not even in a similar technical recruiting position as you were in your previous job. So you were not competing. So no NCA enforceability!
Also, unless your most recent employer requested, at the time of your hiring, that you disclose all NDA/NCO agreements that you had previously signed up to that point I do not believe you were any obligation to disclose and inform them. Furthermore, I think you would have been entitled to defend yourself, ie, hire a lawyer, and not involve your then current employer to defend you.
To be fair I would say you would be wasting your time (and money) attempting to sue your former employer over their lame attempt to enforce an NCO that wouldn’t even apply to you in your new position at you recent company. (If anything you might have a better case and financial outcome suing them for wrongful termination based on a Fabricated allegation.
My advice would be to just move on and chalk it up to bad luck, knowing that it’s very early in your professional career and , as I stated out here, knowing that you have foundational skill sets and attitude to succeed in life. Focus your efforts on finding a new job with a leader/well respected company in a growth market in an industry that interests you and where you can leverage and further develop your skill sets.
Good luck!