@PMenkar1
Maybe a stupid take from me, but can’t u just create a custom property “deal stage copy/backup”
and then at start set this value with the value of the stage when it is set and if the stage changes you copy it over? you can have a counter which goes up set at the start and then filter by this counter to when the deal stage changes again to counteract just overwriting the same property and to ensure having the previous value in there?
Or is this question regarding the source of the property value change? and branching/filtering by that?
i tinkered around with some custom code to get the source of the property value change but this seems overkill
maybe you can elaborate a bit more on the exact workflow/outcome you want to have? 