So I searched a little bit and according to my mushroom-page of trust it is edible: https://www.123pilzsuche.de/daten/details/BlauerTraeuschling.htm (in german).

There it says, that some people do not stomach it well but in general it does not have an exciting flavor and is best be added to other mushrooms. A bit underwhelming...

I will not eat it. xD

Thank you! It really looks very similar and it grew on dead spruce wood, too.