Yes you can change dnd status, infact i was suggested this by jio though the same can be done thru their app or via sms or serviceproviders app. Don't expect much from all this as world wide DND is a flop. Blocking in you phone is the best option till you change your phone. Regarding the app give the reqd permission till you do your work then revoke it.
An example of the result of a complaint
Reference your DND SR# SR0000XXXXX, the concerned operator has reverted that the usage details of the reported number/SMS sender ID do not indicate telemarketing activity. Hence, no action has been taken against the reported number/SMS sender ID."
Yeah, I remember doing that^ so many times that the person who would act on the complains started recognizing me. Because they call the person to tell them that an action has been taking against the complain. (If we've full DND enabled and somebody is still spamming us.)