What kind of files? If it's code, it goes into a repo or a gist. Images/design stuff are best kept with their originating services so the originals can be easily accessed (e.g. Photoshop stuff in Creative Cloud, Figma files in Figma, flowcharts in whatever created them, etc.)

For the occasional one-off screenshot or whatever, we just paste them into Slack because they're not meant to be either permanent or super secure, just a convenient part of a message.

Long-lived stuff that should remain accessible for later people (like third-party PDFs associated with something we build) get uploaded to a Confluence page alongside the rest of the docs for that thingy.

Inside GDrive, teams (instead of individuals) can also own folders/drives, and use that to organize files by roles and then by different folders: https://support.google.com/a/users/answer/7212025?hl=en