About a year ago I returned two laptops that I used for Syncthing that sync my offline password manager and it’s password in a text file in the Sync fodler between both of the computers. They were both running Windows 11 at the time and I decided to return them back to Best Buy but did the ‘erase everything’ option for the Windows reset but I do not remember checking the ‘clean data’ option to yes as shown here: https://support.microsoft.com/en-us/windows/reset-your-pc-0ef73740-b927-549b-b7c9-e6f2b48d275e.
Based on this what are or were the chances of my Syncthing folder being recovered by someone? BTW I used normal syncing.
Unless the folder type was Receive Encrypted, and basing on what you’ve just written, I assume it was not, Syncthing doesn’t do anything to protect files locally. This means that if the drive had not been encrypted (e.g. with BitLocker) in the first place, then yes, it would theoretically still be possible to recover the data even after “erasing everything” (with or without the “clean data” option enabled).
I think this is a data recovery question more than a Syncthing question.
I’m assuming here that you did not check “clean data.”
If the folders and your passwords were on a hard disk, someone reasonably skilled would have a good chance at recovering them with software tools. While I don’t have experience recovering deleted files from an SSD, that seems to be a little tougher.
If someone sent these drives in for professional data recovery, the chances go way up.
EDITED TO ADD: I’m assuming you didn’t use BitLocker or any other disk encryption.