We got a request from a company that wanted to reduce their Google Workspace accounts. They wanted to know what would happen? The client wanted to go from 56 to 46. Here is what happens if you remove accounts.
If you remove the account, all the account data will be deleted (including email), and ten licenses will be free. However, If you just suspend the account then you will still retain the ten licenses as a buffer and the data.
This "suspend" mode will prevent all data from being deleted.
A good CASB will work with you to confirm; don't go willy-nilly and deled because you want to save 40 bucks. Think it through.