Wakanda is a HIGHLY xenophobic totalitarian regime, perpetuated by a viscous blood sport cycle of male violence selecting only the most savage and ruthless to be their leader, that infiltrates outside cultures but violently suppresses any attempt of their members to leave or grow away from their influence. They hoard a natural resource for themselves, depriving their own region of the benefits, much less the world.
The US at least establishes a fairly open world trade network, prevents overly egregious attempts to invade other countries, promotes democracy, womens rights, etc. It's utterly laughable to think that vibranium is in better hands with the Wakandans that it would be with the US. Who, by the way, have full access to hover carriers, iron man repulsor tech, and pym tech yet have not used it for world domination. It was european based Hydra that tried that. Though I am shocked the US allowed New Asgard to go to Norway instead of keeping those highly advanced refugees within the protective bosom of America where they could actually contribute to protecting their new homeland from the various interplanetary threats out there was well as try to preserve the nine realms they used to police and defend and which have BILLIONS of inhabitants. Those folks have responsibilities beyond being a tourist attraction, if only they had proper leadership instead of a drunk.
What version of the MCU are you watching? Bizarro World MCU?
Regardless of what you think of their methods of deciding leadership, the "most savage and ruthless" is obviously not applicable considering the very first duel we see has T'Challa sparing M'Baku.
"infiltrates other cultures" Care to give a significant amount of examples? Also, let's not pretend there's no history of the other way around, oh wait, that scene with Killmonger in the museum where he calls them out on the Wakandan artifact they had in their possession would suggest otherwise……
"violently suppresses" Nakia in Wakanda Forever is living in Haiti, and no one forces her to come back. So your statement is objectively false.
The end of the first BP movie makes it completely clear T'Challa will begin aiding people outside Wakanda with their technology, but they're not giving them vibranium as they know plenty of countries will abuse that power, and Valentina flat out admitting she will use it to strike fear to the rest of the world proves that point.
The US government does not have access to Pym tech, that was a major plot point from the first Ant-man movie. Nor do they have access to most Stark tech, in fact the one time Stark assisted a U.S. government group, SHIELD, in building a major weapon for them……it proceeded to get taken over by HYDRA people who had been working for said US government group (European? Dude, that was WWII HYDRA, the people who were inside SHIELD were obviously mostly American if they worked for such an important American government group that specialized in covert missions, surveillance, and such. This is like looking at an American Neo-Nazi and thinking that makes him automatically German, like dude, a specific fascism movement can spread beyond a country's borders) and nearly wiped out hundreds of millions of people (for the FIRST use of the three ships, mind you) all while being led by a top government official who was even former Secretary of Defense for the US.
Why are you giving the Asgardians shit? Their people have been reduced to insanely small numbers after the attack by Malketh, then the attack by Hela, and finally Thanos killing 50% of them (no, not through the Snap, when he arrives on Thor's ship that had left Asgard after Ragnarok, it's stated he and his forces killed half of those on the ship) and Asgard is no more, they likely lack the materials and such on Earth to properly share what technology they had. And a drunk? I can rewatch Love and Thunder, but I don't remember Valkyrie being drunk while she was on the job.
Like, bro, you clearly need an ENTIRE MCU rewatch if you're getting all this wrong.