Argentina has no fighter aircraft whatsoever, so I think the Brits will be fine.
Doesn’t matter. The next Argie invasion will not be an 80s style soldier invasion. One gray morning, 2 or 3 civilian cargo ships will beach and disgorge 9 or 10 thousand people in civilian clothes, no weapons. The Brits will get 2 or 3 hours notice of they are on the ball. They will outnumber Falkland Islanders by a factor of 3.
Brits going to shoot at the “migrants”? Nope...
They won’t even stop migrants at the Channel.
It’ll be a maritime version of the Green March and the Brits will do nothing except provide food.
A few Brit fighters circling the islands does exactly nothing. And an F-35 doesn’t have the legs to hit the mainland, except a few beach and lonely south of the pampas locales.