Leveling up, won't guarantee a prize/giveaway, I can certainly vouch for that! lol
At present, there are no prizes given to specific levels (not that I'm aware of).
Even the "annual box", isn't guaranteed, and you don't necessarily need to be a certain either, as it's more about likes n activity (obvs activity does go with leveling up, due to experience points etc). I know this is the third year it's been given out, and Anker seems to "tease", there's no guarantee it'll be given again this year (christmas 2019. Thank god it was or I'd have won nothing ocer Crimbo!).
Having g said that, obvs with more activity, come more chances of winning (on the basis... In it, to win it! And if you're active you'll see more giveaways to enter)
Maybe this year they'll be new/extra star people‽