No, you cannot roll back to Old UI from the new one because of the below.
The UI Component is completely managed by SailPoint.
As its SAAS environment, the UI changes are not controlled by us.
As per SailPoint latest communication, this was planned by them where on 2nd Mar,2026, the new UI will be released on all sandbox instances for all customers and PROD go live will happen on 16th Mar,2026. Refer the below post from SailPoint Product Manager.