When backing up folders/files from pc to laptop, using WiFi, the modified dates are not preserved - in case of new folders, that is.
This is based on how Windows handles this.
Directory Opus when copying files folders internally, keeps the original date-time stamps. They figured out a way to overcome this.
I don't know of any backup software (backing up over WiFi) that maintains the original date-time stamp.
BTW: I noticed that when I copy a folder to OneDrive on the PC, the original date is preserved.
When it shows up on the laptop, the modified date is set to today.