There's a game I want to add that has over 10000 views and I did a speedrun of it. I remember trying to submit a game suggestion before but now I can't find it.

If it's not part of a series, you use the "Game & Series Request" option in the support hub. If it is part of a series, you go to the page for the series and either dm the mods about it or use the request game button there.

Note that requesting a game means becoming a moderator for its leaderboard, and you'll need two social media links in your profile & email authentication (2FA) enabled for that.