US ambassadorships to friendly countries are often doled out as political favors rather than to career diplomats, often to people who have raised a lot of money for a candidate’s campaign.

https://en.wikipedia.org/wiki/Campaign_finance_in_the_United_States#Bundling

One consequence of the limitation upon personal contributions from any one individual is that campaigns seek out “bundlers”—people who can gather contributions from many individuals in an organization or community and present the sum to the campaign. Campaigns often recognize these bundlers with honorary titles and, in some cases, exclusive events featuring the candidate.

Although bundling existed in various forms since the enactment of the FECA, bundling became organized in a more structured way in the 2000s, spearheaded by the “Bush Pioneers” for George W. Bush’s 2000 and 2004 presidential campaigns. During the 2008 campaign the six leading primary candidates (three Democratic, three Republican) listed a total of nearly two thousand bundlers.[61]

There has been extensive criticism that US presidents have rewarded bundlers with political appointment, most notably ambassador positions where nominees have no qualifications for appointment.[62][63][64]

If you look at spots like ambassador to China or Russia or something, though, those will go to people with a diplomatic background.