Hi,
MATLAB R2020a supports MacOS Catalina (10.15). For more information, please see our system requirement's page:
You can try opening MATLAB by using the following in command line:
/Applications/MATLAB_R2020a.app/bin/matlab
Just a thought, It is recommended to store MATLAB under C:/ProgramFiles.
If you are still experiencing an issue, please contact MathWorks support: