Potential malware on iPhone

If you did not jailbreak your phone the chances of scammers installing malware via zoom is next to nil. You were probably scared into paying a "ransom" for no reason. Did the scammers/blackmailers send you info that proved they had access to your phone? Probably not.

In any case, for piece of mind, restore your phone as new and not from a backup, as any supposed "malware" will be in the backup.

As the scammers did not confirm they had compromised the phone and you did not jailbreak it, you can safely assume there is no malware installed. So you can restore from backup. I personally like to restore as new (especially with a new phone) because it will flush out old files that are no longer needed and free up space on the iPhone as well as (sometimes) improve battery life.

Backing up from iCloud and Mac is essentially the same. I believe the Mac backup is more "complete".

Backup methods for iPhone, iPad, and iPod touch - Apple Support

iOS / iPadOS devices cannot be infected with Virus / Malware / Spyware *** unless you have intentionally downloaded spurious software or unauthorized apps directly from the internet and installed them on your device or/and have Jailbroken. 

**The primary reason for this is Sandboxing. All third-party apps are “sandboxed”, so they are restricted from accessing files stored by other apps or from making changes to the device. Sandboxing is designed to prevent apps from gathering or modifying information stored by other apps.

Security of runtime process in iOS and iPadOS - Apple Support

The sandbox on an iPhone is a security feature that creates a restricted environment for each app to run in isolation from other apps and the operating system. It is a core component of iOS's security architecture and plays a crucial role in making iPhones more secure.

You have to jailbreak your phone with software. If you did not do this, there is nothing to worry about. I cannot be done remotely.

(see my previous response)