It’s possible to configure Security Settings | Public Key Policies like this example.. (Simply start out by creating a real GPO first like this…)
Then export using PP Settings Manager to an XML. Video of how to do that is here.
Then, upload it to PPCloud. This would make the specified cert Trusted Root CA on the target machines.
What’s not possible is deploing, say, a .PFX file (which is basically cert + private key). This is not possible with Group Policy itself either.
In summary, anything that’s in GP Security Settings | Public Key Policies is also possible once you export then deploy using PPCloud or PolicyPak MDM.
Inside the exported XML you can see the certificate embedded like this and ready for use.