Apple and Google have improved their efforts for direct data transfer. Now, one can easily switch from Google Photos to iCloud Photos. It complements the already existing iCloud to Google Photos transfer support introduced in 2021.

The new offering will come up within the next week. The availability will be through Google Takeout. Users need only to log into Takeout and then select Google Photos for copying.
Back up data for the chosen third-party service. Options include iCloud, Flickr, Microsoft OneDrive, and SmugMug. It creates a copy of the original photos and videos that won’t be touched until users decide to get rid of them.
Not all file types are supported, but the most common—JPG, PNG, GIF—are. Another set of extended formats added are WEBP, AVIF, MP4, MOV, and RAW.

Transferring from Apple to Google may have its own set of limitations. Some formats may not be supported, like Smart Albums and Live Photos. Users will need to independently check for file compatibility before transferring.
The enhanced data transfer functionality previously indicated is aimed at increasing flexibility in the management of photos among users. The enhancement offers flexibility and usability in photo sharing among users. Switching to other platforms is much easier and quicker.