After an interesting journey through installing Python virtual environments and many missing dependencies, I finally got OpenLP to launch without throwing a ton of errors from the terminal.

However, now that it's all up and running with Python 3.9 and being installed from source, I find that I don't get any previews when I load a song or scripture. Any ideas on how to resolve this issue?

You'll need to check your log file or your terminal to see if there are any errors (not warnings, actual errors).