Just go to the service center. They will replace the screen there for free. If there is no water or physical damage. Samsung has officially offered screen replacement for S21, S21+, S21 Ultra, S21FE 5G, and S22Ultra. Till 30 Sep 2024. This policy is applicable one time only within 3 years of handset.
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As per your query, you have already done the possible troubleshooting steps on your device, we would request you kindly visit the service center and inspect your device with the technical team end, they will provide you with all the information in a better way after inspecting the device physically.
