I need more icloud memory and I have the biggets 2tb plan. What can I do?

The only option I know of (not necessarily a good option for many) would be to also subscribe to Apple One. See the following from What happens to your iCloud storage when you sign up for Apple One - Apple Support

If you need more iCloud storage

After you subscribe to Apple One, you can buy more iCloud storage if you need more. With both Apple One and an iCloud+ plan, you can have up to 4TB of total iCloud storage.