Prior year returns cannot be completed or filed online. Rather, you must purchase and download the TT desktop version for each of the those 3 years, and file by mail. You must use a computer (not a phone).
TurboTax® 2017 Tax Software for Filing Past Years’ Taxes, Prior Year Tax Preparation (intuit.com)
TurboTax® 2018 Tax Software for Filing Past Years’ Taxes, Prior Year Tax Preparation (intuit.com)
TurboTax® 2019 Tax Software for Filing Past Years’ Taxes, Prior Year Tax Preparation (intuit.com)
You might wish to consult a local tax preparer due to your 1099 work income those years.
