You can get a Concealed carry permit in most states by doing what you are saying. Take an 8 or 16 hour training course. Here in Nevada it is 4 hours classroom talking about the laws, then 4 hours of Range time where you have to " Qualify" on standard silhouette targets at like 5, 10, and I believe 20ft or so. You only have to fire around 40 rounds, and get a certain number of points to qualify. Honestly you can probably qualify even if you have never fired a gun before ( I personally believe you should get more practice obviously than what is required to just get the permit). I have taken many hours, including the 80 hour course at the police academy back in Ohio that was required to be an armed guard and run an armored car back then.
Now. if you are looking to be able to sell and transfer guns, you will need a FFL license. ( federal firearms license). I have had one of these before for about 5 or 6 years, and it requires a lot more work and registration with the BATF and costs about 550 to 600 dollars a year to maintain. I never transferred, bought or sold enough guns to justify the cost, so I didn't renew a few years back. It used to be handy because you could buy direct from the manufacturers, and save some money that way, and there is no background check. But in the long run, most states (Nevada) after you have your CCW permit, you don't have to pay for backround checks either, and at 25 or 30 dollars each, it saves money getting your permit, and you can usually avoid any waiting period if you have your CCW. With CCW permit in hand, I can walk in and buy just about anything is 10 to 15 min. Takes that much time to fill out the form, and with a permit, you are on your way merchandise in hand.
Another thing, if allowed in your state or jurisdiction you can legally own Class 3 weapons ( Suppressors/ Full-auto/ destructive devices, etc.) This requires a federal " Tax Stamp" that cost 200 dollars per device to get, and is about a 3-4 month wait currently with you needing to get the local law agency ( Sheriff ) to sign off, then file with the BATF, fingerprints and a wait until your background check clears, then you literally get a paper form with a stamp in the corner, and you can then pick up what you bought from your FFL dealer. Research this if you are ever going to get that much into class 3 stuff, as you will want to set up a Trust to keep the weapons registered to, and if you do want to get a suppressor in the long run ( They are cool in my opinion), spend a little more to get one that does multiple calibers, that way you only pay the tax stamp on the " Tube " of the suppressor, and you can buy the different inserts to put inside the tube to run different calibers, but only pay for 1- 200 dollar stamp. My Silencerco silencer ( https://silencerco.com/) can run anything from 9mm caliber up to .45, and just about any rifle caliber available.