Sorry but the 2019 program stopped being supported 11/1/23 so you can no longer download/install/or update the 2019 program on any system. This has nothing to do with the OS you are on.
You should have saved a PDF of the returns you filed so you have access to them anytime you need them. If you need to amend a 2019 return you will need to use paper forms or a local paid tax pro.
