Welcome to the community @Cristiano_battin_i!
How did you install MongoDB? I recommend following the official guide to Installing MongoDB on macOS via brew.
This will set up default directory paths with the expected permissions as well as a brew services definition that will work fine with Catalina.
For more information, see related discussion on Installation issues for MongoDB on Mac OS Catalina - #7 by Stennie_X.
There is no need to run mongod with sudo (or as the root user). Per the general best practice of Principle of least privilege, the mongod process only needs privileges to write to relevant directories including the configured dbPath and log path. Typically there is a specific user & group ID used by the mongod process (and created for you using the official install package).
Regards,
Stennie