Finally, I've found a workaround for this problem. This is obviously a Mac OS compatibility problem of the 2019 version. I confirmed the 2018 version has no issue with Mac OS Catalina 10.15.4.
Here's the workaround:
Click on the Forms button at the top left of the TurboTax window to show your tax forms and worksheets.
Choose Preview from File menu, right below Print... Do not choose Print... or Command P yet. It will hang the app.
A subwindow appears. It seems whatever choice you make here doesn't matter. Just click Preview.
After a few moments the first page, Electronic Filing Instructions shows up in the subwindow. Click Close.
Now choose Print... from File menu. A subwindow shows up and you can choose which form you'd like to print. Click Continue.
After a few moments print subwindow shows up without hanging the app.
I'd recommend choosing All Forms and Worksheets then save as PDF (lower left button) so that you can print the forms as you need without opening TurboTax each time.
Hope this helps.
