Optimal backup

I have recently migrated from a Windows 10 PC (not a Dell) to a Dell Slim ECS1250.  On my old PC there was a 2TB hard drive partitioned by the manufacturer into equal sized C: and D: drives.  I stored my work files in the D: drive.

Under Windows 10 I had an external hard drive of some 250MB attached and the system set to automatically back-up those (chosen by me) work files. It was a kind of set-up and forget and worked perfectly.

Now the new DELL slim ECS1250 has one 2TB hard drive, out of which I can create a D: partition for my work files (as before).  BUT, how do I configure Windows 11 to perform automated back-ups of my work files?  Is using File History an optimal solution, and can this be automated?  Should I also create a complete system back-up (to Dropbox?).  I have created a USB flash recovery drive already.

I think there are more options nowadays than when I first purchased my old PC (10 years ago), so somewhat confused as to what is best optimal solution.

Any help greatly appreciated.