If you want to talk problems, the root problem is the 2nd amendment. It was a noble and possiby genuinely valid sentiment 250 years ago. But as with a lot of things the sentiment it was founded on is now outdated and archaic.
Another big problem (imo) is the way the US population has grown since then (its hard for me to articulate and explain exactly what i mean in english) But in short: the floodgates were opened and a lot of different groups, ethnicities, religious and political views came to the US. Most people came with only two bare hands and most were left to fend for themselves from the get go = lots of tension and aggression + crime is easy) Perpetuate this for a few centuries. It took a long time before the US had any meaningful system of handling immigrants.
Yet another problem is the relative ease of actually aquiring a weapon. Minimal background checks, loopholes and basically over the counter purchasing. When its so easy to get a gun its also so easy to buy a gun off of someone who isnt a licensed dealer.
And like nigafool touched on the 2nd amendment is now become so ingrained into the minds of americans that it if you try to do anything about it, its now all about 'muh rights, mah freedom, its always been this way'
And thats why the solution is so simple but at the same time so hard to implement:
Make it harder to buy guns.
You will hate it and your children probably wont like it. But if thats the reality then in a few generations it will be the new normal and no one will miss the days when you could buy a gun at walmart. Just like no one does in europe and pretty much everywhere else in the world. Its basically a sacrifice you have to make in order to create a better tomorrow for your country (no matter how cliche it sounds) and i get that it fucking sucks for you because youre used to it being like it is now and humans are selfish creatures.