HERE IS THE CURRENT STATUS OF DRAMATICA STORY EXPERT ON CATALINA:
The update to a 64-bit version, Catalina-compatible version of Dramatica Story Expert is still going to be a while -- the update is taking us much longer than anticipated...we've been working on it for a year and a half already. When the update comes out, it will be a free update to all Dramatica Story Expert users. We recommend bookmarking this link to check on the update's progress. (Note: this link mostly focuses on Movie Magic Screenwriter, but the update to Dramatica Story Expert will happen after the Screenwriter update.)
We have developed a workaround for those already on Catalina. Here is a FAQ with directions on how to set up the workaround. We've found the performance of Dramatica Story Expert on the virtual machine running on Mojave is robust.
You may want to look at it to see if it's something you want to do should you choose to update macOS to 10.15 before the truly Catalina-compatible version of Screenwriter is available.