Blacklisted by UK Immigration puts restriction on your entry based on visa breaches, overstays, or forged documents. You can check the status by requesting a SAR from the UK Home Office or reviewing previous visa refusal letters and consulting an immigration lawyer. Blacklisted individuals can appeal to the ban, wait until the ban expires, or correct errors with the assistance of a lawyer. All immigration applications should always have honesty to avoid complication in its processing.
https://www.oasis-india.com/how-to-check-if-youre-blacklisted-by-uk-immigration/