I just purchased a 13 Pro Max with 1TB do I still need to have additional iCloud? Before I decide to cancel that is my question!

There are three major advantages of having iCloud Storage

1. iCloud syncs your iPhone data and keeps backup safely for future use if your iPhone is damaged or lost. The data is safe on iCloud
2. You can save space on your iPhone by keeping low-resolution photos on your iPhone and keep the originals on iCloud. Whenever you open a photo on your iPhone it will fetch the original photo from iCloud and display it to you, provided you have internet. --> Manage your photo and video storage - Apple Support
3. You get more space on iCloud Drive and keep any file on it safely, Also you can view and delete them from any device.

iCloud Drive is part of iCloud Storage. What you store in iCloud Drive counts against your storage limit.

If you purchased an iPhone with 1TB of storage, you will be able to hold a great deal of content on the phone. The use of iCloud would depend on what you have in iCloud. Anything that you use in iCloud, such as Contacts, Calendar, Notes, Photos, etc. would have to be turned on in iCloud on the new device. What space you need in iCloud would depend. If you are using iCloud photos, you would need as much room in iCloud as you would want to save photos for, and they are also synced to your iPhone. After transferring all of your data, you will be able to create a backup and will see how much space you use. You can downgrade your iCloud storage at any time.