https://github.com/Helium314/openboard
Important to note that you need to install a library from inside the app's settings to enable swipe typing. Ctrl+F "enable gesture typing" on the Github page to see where to get it.
No, it's the fork I've linked. You got it from here, yes? Also, the option only appears after you successfully load a library by going to Advanced > Load gesture typing library. Since you said you'd already loaded it I didn't mention that. You might've loaded the incorrect file or something.