I came across this info and thought I share


Steps are given below-
Put the Install macOS Catalina.app file somewhere on the Mac in the user Home Folder (e.g. on the Desktop).
On the Mac with Install macOS Catalina.app file open Terminal and change directory to ../Install macOS Catalina.app/Contents:

in Finder navigate to Install macOS Catalina.app > right-click it > Show Package Contents.
in Terminal window type "cd " - note the space after "d".
drag and drop Contents folder from Finder to Terminal window, so the command will look like:
cd /some_path/Install\ macOS\ Catalina.app/Contents/
hit Enter
Archive "Frameworks" folder by executing the following commands in Terminal:

sudo su
tar -cf Frameworks.tar.gz Frameworks
move the original folder and compressed file in the directory where Install macOS Catalina.app is located:

mv Frameworks.tar.gz ../../
mv Frameworks ../../
In Finder check that in Install macOS Catalina.app/Contents directory there is NO Frameworks.tar.gz file and Frameworks folder.

In Finder check that Frameworks.tar.gz file and Frameworks folder are both located in the same directory where Install macOS Catalina.app is located.

Now copy Install macOS Catalina.app and Frameworks.tar.gz file (Frameworks folder should not be copied) to the SCCM server.

If you need a working .app installer on Mac side, go back to Terminal and move Frameworks folder back to its default directory (make sure this is done after the files are copied on the server):

mv ../../Frameworks ./
On the SCCM server Create macOS Catalina package:

Right-click on Packages in Software Library -; Overview -; Application Management and click Create Package in opened context menu.

Fill in the fields. Check This package contains source files check box, click Browse... and specify the required directory. Click Next in the Package page of the wizard.

Choose Standard program and click Next in Program Type.

At the Standard Program page:

Specify Name.
Use the following Command line:
tar -xf Frameworks.tar.gz -C 'Install macOS Catalina.app/Contents/' && chmod -R 777 'Install macOS Catalina.app' && ./'Install macOS Catalina.app/Contents/Resources/startosinstall' --agreetolicense

Set Run mode to Run with administrative rights.
Tick Allow users to view and interact with the program installation checkbox.
Click Next.
Leave other field values in the wizard as is.
Configure properties of the package to copy its content to distribution point:

Right-click on the macOS Catalina package in Software Library > Overview > Application Management > Packages and click Properties in the opened context menu.
Check Copy the content in this package to a package share on distribution points checkbox in the Data Access tab of the package properties dialog.

Apply changes and close the dialog.

Deploy the macOS Catalina package:

Right-click on macOS Catalina package in Software Library > Overview > Application Management > Packages > Deploy.
Choose the required collection the "General" page of the wizard.

Add Distribution Point on the Content page of the wizard.

Add assignment schedule Assign immediately after this event: As soon as possible.

Leave other parameters as is.