Copy (sync) timestamps only of already copied files and folders in Windows
Solution 1:
Ok, I've managed to do this maybe it will be useful for someone else:
robocopy /e /timfix /dcopy:t c:\source d:\destination
Does the job :)
Solution 2:
Copying it again might be the fastest method. Attended oversight of all commands took me hours and it wasn't perfect. To avoid file copy, added copy:t
robocopy /e /timfix /dcopy:t /copy:t c:\source d:\destination
indeed robocopy started physical copying without it (Windows 10 local or Samba). Needed to fix terabytes of Samba data wrongly copied without time part of timestamp thanks to linux abbreviation of "older timestamps" (time is not shown, and other commands treat it as midnight when copying). The result locally is ok but only modified time is copied in (FreeBSD) Samba. Creation time is not supported by robocopy time fix here, only when file is recreated.
A glitch of robocopy is it reports 'copied bytes' even if data was not copied, as unrealistic speed shows: Speed : 2826677.309 MegaBytes/min.