...high-powered rifles such as AK-47s, 9mm pistols, sniper rifles and machine guns.
AK-47 is of intermediate power, about like a .30-30, AK-74, similar to .223.
9mm pistols are common as cat crap. They're used worldwide.
Sniper Rifles. While they may be getting some of those $5,000 and up actual sniper rifles, that's pretty spendy when they could just be buying some cheap surplus bolt actions somewhere.
"machine guns". Don't look for American gun owners to pony up a bunch of these, especially anything made
since 1986, because they are illegal for the average person.
Older full auto firearms,
made before 1986 can be bought with the permits, taxes and deep pockets, but are heavily regulated and not likely at all to be sold off to Haitians, or anyone else, for that mattter.
But Joe Biden imported so many people from so many places, it's entirely possible he brought in some Haitians with criminal connections or links to arms dealers who can pick those things up on the down-low..
To say things have been a mess there for a while would tend toward understatement, but I foresee a return to a warlord style dictator, and that wasn't pleasant for most.