What is an unlicensed gunsmith? I have a buddy who works on firearms as a hobby, one of the best old school gunsmiths I've ever seen. Why does he need government permission to continue his hobby? Unlicensed dealer is a backdoor the government is already pursuing, trying to do the Universal Background Checks, AKA universal registration, so private sales are illegal. I have done private sales my entire life - heck, I've GIVEN guns away in the past. As long as I meet state law, (which states if the buyer is a prohibited possessor, it is on ME), then I should be left alone.
Unlicensed manufacturer - goes right back to the argument the government is using, "nobody should make guns without our permission". If you are making guns to supply gangbangers, then you go down for selling to prohibited persons and don't let the damn attorney's plead it away! Most gun charges are pled away WAY before they get to sentencing. Refer to Project Exile to see how it works when properly used. But, I digress - if you are making guns for yourself, no permission slip needed. I honestly believe if you are making guns for family and friends, NO LICENSE SHOULD BE NEEDED. That IS how this country started, and would the requirement to be licensed as a manufacturer stand up to the Bruen test? Probably not, I don't know - was Colt "licensed" by the government when they were making 1860s for the Civil War? I honestly don't know.
Unauthorized creation of NFA - OK, pie in the sky time, I think that should be at the same level of any other firearm or firearm device. That's how innovation was done over the centuries, maybe there is a kid out there who has a mechanical knack and a great design in his head for the next machinegun or better suppressor...but he doesn't want to go to prison for experimenting, so off to Deisel Mechanic school he goes. OK, extreme example, but NFA was the first gun control law in direct violation of the 2A and should be struck down in it's entirety, but reality says THAT ain't likely to happen while I am still alive. Other than those points I largely agree with your position.