If you submit a patent application after the competition, the publicity of your entries will affect the novelty of your patent application, and the patent application will be rejected.
Even if it is authorized by luck, others can invalidate your patent on this basis.
So it is safest to file a patent application first, and there is a closed period for filing a patent application. The utility model and design take several months, and the invention takes 18 months. During this period, no one can find out except the examiner. You can rest assured that your work will not be copied by others.