Google offers a handy tool to help you free up storage space in your Google Cloud storage account.
Start by following this link: https://one.google.com/storage/management
Manage your account storage will open.
You can start by checking out deleted files and emails and spam.
Choose which items you want to get rid of.
Then you can check out large files stored in files or attached to an email.
Google will also find other items like unsupported videos that you may wish to delete.