Backing up with Time Machine

Time Machine is a local backup for your Mac.

It can be use to fully restore your Mac or Migrate to a new Mac.

Back up your Mac with Time Machine - Apple Support

iCloud is for storing and sharing data between your Mac and iOS devices.

It can only fully backup your iPhone and iPad.

iCloud+ - Apple

No. Time Machine can't back up to the cloud.

(243593)

As mentioned Time Machine is your backup. iCloud is NOT a backup plan, it is a method to make data available on multiple devices simultaneously.