One unexpected culprit behind slow Google Drive is your device! Outdated hardware can slow down the upload, especially if you're running multiple tasks simultaneously.
On Windows, you can check your hardware specs by opening Control Panel and then clicking System. Windows should automatically detect settings of your hardware. If you're not tech-savvy, compare your processor and RAM to modern standards. Ideally, modern PCs should have at least 8GBs of RAM.
For Macs, click on the Apple logo and select "About this Mac"