If you’re on Android, that’s probably the most important thing to consider first. Just using a phone with Google Play Services gives up a great deal of privacy, even if you think you’ve turned all that off.
So, consider either an iPhone or if you’re really serious about this shit, GrapheneOS. The iPhone is easier for average people, but GrapheneOS is more private and you have more control. Both are better than Googled Android.
For a Google Drive alternative, that’s simple. If you’re already using Proton, get ProtonDrive.
For Google Docs alternative, that’s a bit more challenging. There aren’t any direct competitors with full end-to-end encryption that are any good and also cross-platform.