Question about AsRock AB350M Pro4

It worked for me after I swapped the Rams (change slot, try, etc.). I don't know exactly which configuration I used, but I somehow got into the bios. With a ryzen 7 2700x

I doubt it. It probably won't work. The only possibility would be that the board is already shipped from the factory with the latest bios that supports Ryzen 2xxx. So you would have to know the production date beforehand and whether the manufacturer also does this.
I would rather ask digitec directly whether they know which version of the board or bios they are selling.