This did happen to me. I purchased a renewed S21 off Amazon. As part of the refurbishing process, they replaced the battery and screen, so it looked new. Once I finished the setup process and everything was working fine, I allowed the OTA update from One UI 6.0 to 6.1 and the touch screen became unresponsive.
I later found out it is indeed due to a bug in the 6.1 update that affects "some" users touch screen and nearly all persons with screen replacements, regardless of the method of replacements, Samsung official or otherwise. Unfortunately, Amazon and other sellers do not disclose this information, so we are all finding out like this, on this thread.
Having said that Amazon was willing to replace it or refund as you have 90 days to return/replace however I would have needed to send back the phone first which would not have been to the local warehouse it came from but the regional office, wait for them verify everything and receive it and then process a return/refund.
So instead, I found a local cell phone repair shop who flashed the ROM back to the 6.0 for $25. That took more time to drive to shop then to actually flash the phone. I was in and out in 15 minutes. Once I got home finished setting up the phone, I turned off the OTA updates and Automatic updates.
The issue is with both Samsung and your carrier where there is that bug in the OTA updates. And even though they claim they stopped the update to fix the bug and then began re rolling out the updates after fixing it, clearly, they did not fix it. And they both just point the finger back at each other.
