I’m not doing it this year but I did it in 5th grade, 7th grade and 8th grade.
Me and my group ended up getting into state writing a 50 page essay on Historical Writing (basically why and how language has evolved the way it has in the past, what writing utensils were used at each point in history and what reasons it was invented for, and how the course of history could have changed without language and writing and so on). - (I would not recommend writing over a 5,000 word limit as we got marked down by that)
Then I got into county for creating a website on Women In Aviation. (I got 3rd place in county, which was quite good as I don’t have too much experience with website design).
In eighth grade, I did an Exhibit on Paralympic Sports and the triumphs and tragedies they had to face to achieve top levels into their sports. I didn’t compete but did it as it was just a personal project to motivate my peers that nothing is impossible.
I wish you luck!