More storage

Not an inexpensive option, but you can have up to 4TB if you subscribe to Apple One.

See the following from What happens to your iCloud storage when you sign up for Apple One - Apple Support

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.

Also see: Apple One - Apple

See the following from my original reply:

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.

The highest price Apple One plan is 2TB -- but after you are subscribed to that plan you can then purchase 2TB more.

amsconberg wrote:

I don't see anywhere on Apple One that I could get up to 4 TB. I wonder if it is better to have a different Apple ID for personal and professional.

It may be -- but you will need to decide that as I have no idea how much storage you need for each of those and whether having other things (e.g., Contacts) stored separately will work for your situation.