Codex_
I went ahead and posted a bug report since using a null value or any invalid value will no longer work in the .ini file. It worked in 2020.2, but not in 2020.3. I got a response already.
See bug report and response here:
https://bugs.kali.org/view.php?id=6727
Bottom Line, the .ini file fontFamily must have a valid value now. The update fixed the terminal to correctly look for Fire Cuda and not FireCuda (no space). The real issue is with the Qt library which is not within Kali team's scope to fix.