I know that lightroom normally don't touch the original file, but it saves the different editing steps which you have done. The thing is, that you are only able to have a look at the edited picture in LR.
As I have saved my files on a NAS, I am accessing my fotos also within other apps oder file explorers and this leads to my question.
Is there any way to export the edited file and save the steps on this file to have the possibility to roll back? So basically the edited picture is saved on the harddisk and the steps to roll back are stored in LR?
If not, how do you handle this topic or do you access your picture only with LR?
Whenever you have need of an image version that shows your LrC editing, but that you can access in some way from outside of Lightroom Classic, you will need to Export that (or Publish / Print / generate a web Gallery or Book or Slideshow).
Output produces an independent, standalone copy. The production of this reflects - though not separably - the imported original plus all the adjustments that were in place at the time of export. This is effectively all-or-nothing.
(there is a special case of exporting in "Original" format - but that will not then make LrC editing visible except when brought back into Lightroom or ACR. And even that special case only includes one set of adjustments: those that were in place at time of export, without including any alternative develop History states)
But everything DOES remain still separately retrievable, and further variable, within the Catalog environment.
Any given Exported version is ephemera: it might be kept forever, or it might be disposable the moment its immediate purpose is served (or something in between - no matter).
An exported JPG file, for example, can be thought of in similar terms to a physical print on paper. If you ever need another, you'll make another then. By this account, Lightroom is a "machine" for producing physical or digital output, in the same sense that the entire apparatus and stock of negatives and chemicals etc that constitute a traditional photographic Darkroom, are a "machine" for producing photographic prints.
The idea is that thanks to the continuing availability of the imported original, and of your sequential History of applied adjustments within the Catalog: you retain indefinitely the means to export again at will.
The same way as before, or some other way to suit a different requirement. Also, showing the same editing as before (referring to a virtual "snapshot" / History state of those adjustments), or else now showing some different editing instead.