Seems some have trouble trying to get Apple’s Time Machine to properly restore from a Time Machine backed up to the My Cloud. Here is one recent thread:
https://community.wd.com/t/cant-connect-wd-mycloud-to-time-machine/163150
Can you copy the Time Machine Share/Folder from the My Cloud to a portable/external USB hard drive? Yes.
See the following Apple documents for more information on using Migration Assistant or Time Machine.
Move your content to a new Mac: https://support.apple.com/en-us/HT204350
Use Time Machine to back up or restore your Mac: https://support.apple.com/en-us/HT201250
