Turbotax does not support 2018 and 2019. in any case if you're due a refund it is lost because you didn't file timely. if you owe the IRS can come after you at any time. Penalties and interest increase each month.
for 2020 and 2021 and even 2022 you need the desktop app - full pc or mac. 2020 and 2021 cannot be e-filed and soon that will be true of 2022.
