can t upload custom process template in Azure DevOps Server 2020

Question

I'm trying to create a custom process template in Azure DevOps Server 2020. I'm using the on-premises XML process model. When I upload my custom process template I keep getting a 'You can't update a system process' error.

These are the steps I took:

1. Downloaded the Agile system process by going to Collection Settings->Process, clicking on Agile, and choosing 'Export'.
2. I unzipped the downloaded folder and opened it in Visual Studio.
3. I made changes to field names and added new states for bugs.
4. I changed the name and version in the ProcessTemplate.xml like so:

<metadata>

<name>CustomProcess</name>

<description>This is a custom process template based on the Agile process</description>

<version type="ADCC42AB-9882-485E-A3ED-7678F01F66BC" major="1" minor="0" />

1. I renamed the folder to CustomProcess and zipped it.
2. In Collection Settings->Process, I clicked on 'Upload process template' and tried to upload my CustomProcess zipped folder. I get the error 'You can't update a system process'.

I made sure to update the name and version as suggested in a previous Stackoverflow post but I still get an error. Is there something else I need to modify in the XML files?