You said "My higher paying job isn't taking federal taxes out." Are they treating you as an employee or as an independent contractor? Do you get a W-2 from that job or a 1099-NEC (or no tax form)? Are they taking out Social Security and Medicare taxes, or do you get the full $20.80 per hour with no deductions?
You asked about "my W4." That sounds like you only have one W-4. But if the first job is treating you as an employee, you have to give a W-4 to both employers. The two W-4s will probably be different. The IRS Tax Withholding Estimator at the link that DoninGA gave you will show you what to put on the W-4 for each employer.
If the first job is treating you as an independent contractor, then you are self-employed and the income is self-employment income. You probably would not be able to have enough tax withheld from the second job to cover the tax on the self-employment income, so you would have to make estimated tax payments during the year.
Since this year is almost over, you might not be able to have enough tax withheld for the rest of 2024 to avoid owing on your tax return. When you get your first paychecks from each job in 2025, go back to the IRS Tax Withholding Estimator and adjust your W-4s for 2025.
