You can claim a deduction for the business percentage of phone use based on the number of hours you were available for DoorDash and UberEats. You could also get a “family plan” and deduct 100% of the cost of a second line for business.
If you get audited, you will have to explain to the IRS how you came up with the business use percentage, so keep some types of records of the total hours you were doing DoorDash and UberEats, for example.
TurboTax says:
“If you're self-employed and you use your cellphone for business, you can claim the business use of your phone as a tax deduction. If 30 percent of your time on the phone is spent on business, you could legitimately deduct 30 percent of your phone bill.
Alternatively, you could get a second phone and use it exclusively for business.”
See Can Cellphone Expenses Be Tax Deductible with a Business?