deducting race entry fees for a YouTube channel

Yes, If the sponsors give you a 1099-NEC for payments then you are self-employed and you can deduct all expenses connected with the business.

Follow the steps to enter expenses

1. Type Schedule C in the Search box
2. Select the Jump to the link
3. Answer Yes to Did you have any self-employment income or expenses? and answer the questions until you get the What kind of expenses did you have screen. Select your expenses, then Continue Add expenses for this work
4. Select Start next to an expense type that you had
5. Enter your expense description and amount, and answer any other questions we ask

If you get a W-2 then you will not be able to deduct any expenses.

Click on the link for more information

Self Employed