Add rows based on Date Range in Power Query

Hi all,

I have a Date Range Query that looks like this in Power Query:

Now I have a huge price list with all sorts off materials that have a random price validity period:

And here is my goal query (just an excerpt with two stores...list is actually very long):

I tried it with a left join with the goal to do a fill down afterwards, but it doesn't work.

Thanks for your kind support!