There's a solid educational consensus on how to become the best at something: do it a lot.
If your goal is to winning contests, you should really prioritize cranking through them: getting practice at getting better. Don't try to make a masterpiece. Instead focus on becoming fast at creating entries, doing them according to the rules, and sending them off. Like those studies where people who made 1,000 good-enough vases were better at the average one than people who tried to make 100 beautiful ones - even when the goal was 'create a beautiful vase'.
But then, if you're a professional contest-enterer, that's got do a lot to boost your chances - especially over time, right? At the 1 year mark, I would expect you could raise your chances to 10% of a win of some type per contest (being conservative here). You've specialized in this. You'll always be a contender.
And that number's high enough that, if you enter 10 a day, that seems closer to the optimum. You are playing a numbers game on the strength of your numbers.
By analogy, this is like picking an index fund and continuously investing, rather than trying to pick that one stock that's going to the moon.