What happens when you try to download the desktop editions after purchase from this TurboTax website - https://turbotax.intuit.com/personal-taxes/past-years-products/
Note - If you are amending the 2018 tax return for a tax refund and did NOT file an extension for the original 2018 tax return, the tax refund will not be paid since it past the three year limit for filing. The 2018 return without extension had to be filed on or before April 15, 2022 for a tax refund.