No, you should not upload your OBC certificate to the DU CSAS form if you belong to the OBC creamy layer.

Delhi University requires candidates claiming reservation benefits under the OBC category to belong to the "Non-Creamy Layer." This means their family income falls below a specific threshold set by the government. OBC creamy layer candidates are not eligible for OBC reservation benefits in educational institutions. Uploading your OBC certificate in this case might lead to complications during verification or disqualify you from claiming OBC reservation.
During the DU CSAS application process, you should select the "General Category" when asked about your caste category.

If you have a valid, recent (issued after March 31st, 2021) OBC Non-Creamy Layer certificate, you can consider applying under the OBC category. However, confirm your eligibility based on your family income not exceeding the creamy layer limit set by the government.

Ihope it helps!