No, there is no converter that does this automatically.

However, With your 2020 Proseries license, you should have access to prior year Proseries 2019. Contact customer service if you do not see it available for download in your account. 

You can change the extension of the 2019 turbo tax files from .2019tax to the correct proseries extension( .19i  for indiv. This will be different for business returns)

Once you have the files in the 2019 Proseries, you will not be able to open them without charge, but they will be available for transfer to the 2020 ProSeries program.