but wtf is a lawyer gonna be able to do besides represent me if shit goes sideways?
Well, they'd be able to explain better how this all works. Whether this would actually be considered an involuntary commitment and what you should do about it to avoid shit going sideways in the first place
Most (all?) states have a link on their bar association website to a list of lawyers who will give free or cheap 30-minute consultations, too. So if you don't need one, or if the answer is readily apparent to a lawyer in that area but not to you (fairly likely), you shouldn't need to break the bank to find out.
They can also advise you about what the possible outcome(s) may be before you do anything, so you're prepared ahead of time.
Do background checks look at internet history? Cause if so we're all fucked lel
I feel like your prospects of getting arrested/taken in by authorities because you lied/misrepresented yourself on a form 4473 is pretty low but you're definitely right in seeking some legal advice on this - your state's definition of "involuntary commitment" may differ from the federal one.