What specific data gets backed up when a backup is performed

I may have to reset to factory settings and do a backup/restore. My question how much of my user data is being restored? Does it save the wifi password ?  I have a huge list of ports being forwarded, range extender and so on.  Everything works as it should and I hate to mess with it. The only reason I would consider resetting to factory is because of a custom service rule conflict in port forwarding. The router is saying that the port is being used when it is not.  I was able to confirm this with port finder software and the port range is not already used in my list of ports being forwarded. The problem came about when I wanted to edit the custom service to use another computers internal IP address on my network.  It is apparently a known issue for years and I have not found a solution to fix it other than factory rest.

Windows 10, 64 bit

Google Chrome