I've been using and loving Spark on a Mac for many years. When I recently I updated to Catalina, the Text/Keyboard feature stopped working. I looked around for an alternate app but couldn't find one with a feature equivalent to Spark's Text/Keyboard, including the similar native feature in Catalina. Finally I found the review of Spark by Joe H. on this page, which solved the problem completely. In case you can't find it, here's a quote of the relevant parts:
"Make sure to use the latest version of Spark (which is currently 3.2.1 : see (my) other comments below). The only place where you can see the correct version number is when you open the app and choose "About Spark" from the menu. To make all features function: go to your System Preferences > Security & Privacy > Privacy > Accessibility and remove the Spark app, and add it again. You might have to repeat this step, and even try a reboot. Also: in between creating or altering shortcuts it can help to stop & start the Spark Daemon. You also might have to start the Daemon manually after every boot/login." Happy Sparking!