Yes, you can unfollow 1000 account on Instagram at once by taking the help of any third party application. Third party app will create a segment of your follower list according multiple criteria and then you can unfollow all the accounts at once.
But if you are new user or your account not much old then do not try to perform activities in bulk because this leads to suspension or blocking of your profile
Read the detailed guide to mass unfollow on Instagram: https://ityug247.com/how-to-mass-unfollow-on-instagram/
