How were you able to get Samsung to issue you a replacement phone before returning the defective phone? I am having the exact same issue with my S21 Plus restarting as you did. Samsung is insisting that I send my phone to Texas for a second evaluation (an authorized Samsung Repair Center already evaluated it and deemed the phone unrepairable). This issue of random, frequent restarts is a known problem with the Samsung S21 series according to the technician at the authorized Samsung Repair Center and numerous comments on these forums for the S21 on Samsung Community and elsewhere. It is clear that the ONLY solution is to either replace the motherboard or get a replacement phone. While the hardware problem is annoying, what is unacceptable is how Samsung makes it unduly burdensome to get a replacement phone by insisting I send it in -- and thus leaving me without a phone for a week (or more). I would like the same solution they offered you, i.e. to get the replacement phone first, make the transfer, and only then return the defective device. This seems a reasonable expectation for a known problem on a premium phone that commands a premium price of $1,000 and is the level of customer service that is commensurate with its competitors, such as Apple which would have simply replaced my phone at the authorized repair center.
