FreeFileSync is a good option if you have been looking for a GUI-based Windows program to compare directories or sync directories (kind of like rsync).
In the GUI, pick two directories and the tool allows you to compare or sync between them.
Compare can be done using file time and size (fast) or file contents (slow).
Sync can be one of one-way mirror, two-way sync or update. This is way faster than copying over directory to another using File Explorer, since only the files that are different would be synced.
Tried with: FreeFileSync 11.13 and Windows 10 x64