Yes, that’s possible as long as you are synchronizing the Case object along with your Sales/Service Cloud data.
If yes, then it should be already included in the data model and ready to use.
In the Decision split, choose “Contact Data” and find the Case object, then create a filter based on the status.
Contact Data is the most up-to-date data about the ...
Figured out the issue. I didn't test by sending and replying to the Proxy email designated in the email-to-case setting. It also requires the setting of including the thread ID in the subject or body also located in the Email-to-case setting.
Probably a bit late but better than never.
You can use sfdx force:mdapi:deploy -d data/standard-object-stub/ -w 1 -u $SCRATCH_ORG_ALIAS with a package.xml that references a Case.object file with the following content in a objects subfolder before you deploy your sources
<?xml version="1.0" encoding="UTF-8"?>