Don't rely on the "How to pronounce Sukkot" video on YouTube. It's a computer voice with a British accent that is actually trying to say Sukkos. Don't bother with this other computer-generated-Brit sound file either and for the same reason.
There is actually not an accented syllable difference between Hebrew and Americans using Sephardi pronunciation: SuKOT. When you get into American Ashkenazi-speak, the accented syllable changes: SUKkus.
A minor difference you may have noticed above: I only included one K in the Sephardi pronunciation. You don't hear Suk-KOT, instead you hear Su-KOT. The Ashkenazi Americans have a K sound in both syllables: SUK-kus.
The U is pronounced "oo" as in "suit." The O is pronounced as a long O sound, like "coat."
American Ashkenazi Vowels
The U is pronounced "uh" like book. The second syllable is not pronounced like "us" the word, but it's very close. I can't think of an English word, but there is the Yiddish word shtus (silliness, nonsense, stupidity, junk/crap as a value judgment). Maybe this vowel sound doesn't exist in English...
But whatever you do, don't pronounce it "suck-it." That's one of my favorite "Oh no, what did I say?!" moments ever, and this time, it wasn't me!