As far as I know the only way to do that would be create catalogues for those files. Some don't recommend that. Unless you know how to code but I doubt that would be a very good idea. The catalogue is just a record of your adjustments. You can back that up yourself and/or set it up to back up when you shut LR down. Presets are stored OS. On a Mac in the user library. You should back your computer on a separate drive and everything will be there to work with later. If your files are on an ED then they shod be backed up as well.
So basically my HD is backed up onto an ED using Time Machine. Catalogue and presets are there. All my files on a different 6TB ED and backed up to a another drive. Later if you need to import anything just re-establish the links between the catalogue and files, if you need to.
Unless you specify a location LR places the catalogue. On a Mac this is in Pictures. This is backed up to an ED by Time Machine. Can't hurt to save the catalogue somewhere else once in a while if you want to. Before LR7 merged with the LR6 catalogue I saved it in case I drop the plan. Not sure I can go back to LR6. I'll still have uses for CS6.
It’s simple. Everything is on your internal hard disk, except for things that you deliberately place on external disks (images, perhaps your catalog). So make regular backups of your entire internal disk, and of those external disks if you use those.
Suppose I set up a new Windows on a new computer, how can I transfer all (or some / a part) of the data (develop settings, settings, presets, self created presets and so on) to the new Windows / operating system? Without having to re-create / set up all the presets again, e.g. add them to Lightroom, add presets to the "Favorites" in Lightroom, etc.? And may be I do not want to copy / move the images already being edited completely, but only the ones, not being edited.
Or, how can one transfer all of one's old data from a Lightroom to another Lightroom?
As far as I know the only way to do that would be create catalogues for those files.
Thank you for the link. So, to transfer all of one's own data (presets, develop settings, etc.) in Lightroom to another Lightroom one would have to manually copy all of them separately? And after re-set them? There is no option which does it in a single step?
Unfortunately not. (Yet I seem to recall, long ago, a program that might do this. My memory does not recall any details)
Here is Victoria's blog on transferring to a new computer- How do I move Lightroom to a new computer? | The Lightroom Queen
If you have made a full system backup on an external drive, you will have it to selectively restore Presets, Templates, etc, at any time on the new computer system.
I always keep a saved backup of two system folders for that reason- C:\ProgramData C:\Users\MyName\AppData (OS folders)
"And after re-set them?"
I would describe this as- After installing Lightroom on the new computer, selectively Copy the folders with your Presets and Templates, etc, from the saved backups to the new computer over-writing the existing folders. (You should have the names of the essential folders from Lightroom Classic File Locations | The Lightroom Queen )