Google Ads seems to now have PMax, Performance Max, channel reporting on the account level. This allows you to compare multiple PMax campaigns on the same screen, the same report.
This was spotted by Thomas Eccel who posted about it on LinkedIn. He said, "You can now analyze and compare multiple PMax campaings on the Account Level!" "Also, Google's wording indirectly indicate that more campaigns might get a Channel Reporting," he added.
PMax Channel Reporting used to be available only when selecting a specific PMax campaign.
He shared this screenshot (with all his marketing) for you all to see it:
Forum discussion at LinkedIn.