sweepstakes contest :unlimited xbox game pass ultimate

No. The sweepstakes ends on December 15. After that, they'll have a drawing and then contact the winners. They try to contact the winners within 1 week of the drawing.

It was an achievement contest for last month (May 2021) to win an Xbox seriesX by trying to earn as many achievement points as you possibly could in the zombie games that were listed on the contest page. The top 5 players who earned the most achievement points during May 2021 playing the Zombie games listed on the contest page and available to play via Xbox Ultimate game pass or Xbox game pass won an Xbox Series X. Rules stated you must have a membership to either ultimate game pass or game pass. I've actually taken part in multiple of these contest including this new 1 this month June 2021 for the same prize and same top 5 who earn most achievement points except this time it's Sports games instead of Zombie games

There's no such thing as a Gold Unlimited. Did you buy Xbox Gold or Game Pass Ultimate?

Gold only allows to you play online multiplayer. Game Pass is like Netflix for games and allows you access to a library of games to play. Game Pass Ultimate includes both, If you only bought Gold, you would either need to buy Game Pass as well to access the game or buy the game.

Have you joined Game Pass Ultimate in the past or Spotify unlimited? If so, you may be ineligible, unfortunately. It's for new customers to bother.

Well its unlimited access to a library games, made by many different publishers / devs. Here's a LINK to a list of the games included in the Ultimate game
pass library, in case you change your mind.