The problem of disarming is that it really needs
100% compliance. We can fantasize about that.
But it won't happen.
Another option has been offered. Yet given the current mentality with arms and the distrust of police forces, it is going to have to transition over a couple of generations.
Thus if we consider this,
"...Compose your differences, and reduce your armaments, that the burden of your expenditures may be lightened, and that your minds and hearts may be tranquillized. Heal the dissensions that divide you, and ye will no longer be in need of any armaments except what the protection of your cities and territories demandeth...."
That would bring up options.
National arms are reduced to only what is requires to adequately police each Nation. Private citizens do not need arms. (I was in the army, was an avid gun owner, had 2 x SKK 30 mag semi automatic, a 7.62 Sniper, a 6.5 Mauser and a .22 Magnum.) I was rid of them all in the Australian buy back, they were all scrapped. Thank goodness for that.
An international force would be well equiped, represented by troops drawn from all Nations.
The Boundaries of Nations would be set and if any Nation then raised against another, the International force could be deployed to subdue that Nation into total submission.
Lots to decide, but that's a start.
Regards Tony