Are the various alien cultures in trek supposed to reflect the various governments of earth today?

No, not Today, but yes, the cultures of 50 YEARS ago, for the original series and The times of the other series and .movies were made. Star Trek was and still IS a social commentary. This is WHY more than once I have asked WHAT has happened yo the IDIC philosophy. Please Google it.

So were Looney Tunes and Bugs Bunny and various Warner Brothers and Hanna Barbara cartoons. I didn't like Bugs Bunny that much when I was 4 years old, but that changed as I grew up. Star Trek The original series premiered when I was 13 and half years old Star Trek was part, but NOT ALL of the reason I became a scientist as well as an historian. MANY scientists became scientists. NOW we are retiring or getting fired or let go because of our ages.

Voyage of the Beagle, by Darwin, five-year HMS Beagle mission to the Galapagos, The Voyage of the Space Beagle (1950) science fiction novel by Canadian-American writer A. E. van Vogt. An example of space opera subgenre, the novel is a "fix-up" compilation of four previously published stories: Gene Roddenberry, Star Trek, the name trek was used in stories about wagons going out West to San Francisco, a 'Western trek' in outer space.

Too much time on your hands? Try watching Discovery or Orville. They're pretty good.

No.

Imagine a version of the British in The Federation - "We want to leave...We can do much better on our own, W edon't need your starships to protect us we've got our own...We'll just trade with the Romulans". Meanwhile the Vulcans looks puzzled.