Google’s fixing a cookie problem with Drive downloads, but not the biggest one
However, while we interpreted the original post as applying to all downloads from Google Drive, Google has updated its post on the Workspace Updates blog to clarify that this doesn’t change anything if you’re using the site directly. For anyone using Chrome with third-party cookies blocked, this workaround to manually unblock third-party cookies just for Google Drive is still required to enable downloads directly within Google’s service on Google’s browser for the foreseeable future.
Google’s blog post doesn’t explain why Google Drive currently relies on third-party cookies, but there’s speculation that it’s because the service uses a separate domain (googleusercontent.com) to host content uploaded by users as a security measure. The cookies are then used to verify that you have permission to download a given file.
Correction October 20th, 2:27PM ET: Google’s post originally read, “Starting January 2, 2024, Drive will start serving downloads without requiring third-party cookies.” After publication, the post has been updated to add a clarifying statement that “This is separate from downloading files from Drive.”
https://www.theverge.com/2023/10/17/23920504/google-drive-third-party-cookies-download-fix