I want a copy of all new or updated files synced with two matching folders on my Win 10 PC.
This step is easy.
I then want to FTP any new or updated files in one of these folders to my website on my Linux shared hosting account.
Now it depends, if you really need to re-apply the changes from the previous step (that's not easy, but doable), or if just want to do a new blind synchronization of the Windows 10 folder to the remote Unix machine (that's basically the same task as the first one, hence easy).
In any case, as you need to schedule the task, you have to write a script. WinSCP can generate it for you:
Just make sure you select "New and updated files only" in transfer settings, before getting the script generated:
For a scheduling part, see: