Studio Operations shows where account closure will live, but the control is deliberately unavailable during development so studio data cannot be deleted by accident.
Find the account-closure control
Settings → Account → Close your account
The Close account button is disabled in the current development build. That is expected.
Do not confuse this with cancelling a plan
Settings → Subscription
Closing your Studio Operations account and changing or cancelling a subscription are different actions.
If you need help while closure is unavailable
Use the relevant Help Guide or Guided Help first. If an account action is unavailable and you still need assistance, contact Studio Operations Support.