Pokemon Sword & Shield are under fire for their shortcomings but it's important to filter out the fake accusations. One such accusation is regarding wipes of all saves on a Switch, but this seems to be a baseless rumour that latched onto a different issue.
Hating on Pokemon Sword & Shield is trending now thanks to the creative direction Game Freak decided to go with but there are also some false accusations. Rumours of the twin titles corrupting saves of not only themselves but other games too are circulating in less than true fashion.
The original allegation was that all SD card data was wiped, including Sword & Shield saves but this didn't make much sense as the saves were located on Switch's internal memory. Upon the collective effort of the Pokemon community, several other reasons for corruptions came to light.
One of the biggest culprits are files saved in the exFAT format. The platform has apparently had issues with such files ever since its launch and Nintendo's faulty driver is to blame for any problems caused. Furthermore, even the issues with the format cannot harm save files , let alone delete save data related to other games. The only files that can be lost in this case are the ones stored on the SD card.
Speaking of SDs, these can be the second issue that can cause problems. Apparently, some of the players that encountered data corruption used cheap SD cards that may have been the source of the problems.
Summa summarum , Pokemon Sword & Shield are under a lot of heat after Game Freak made some questionable development choices but the games do not contain a bug that deletes save data, be it their own or that of other games. Oh, and avoid using exFAT format.