Just in case anyone is still reading and or trying to help. I think I am finished now including good prices
https://de.pcpartpicker.com/list/h4DqzY
Feedback welcome
Will buy in the next week

You don't need an M.2 cooler. Your board comes with a passive M.2 heatsink.

Also, don't buy that M.2.

Either go with a regular SATA M.2 and buy the Crucial MX500.
OR if you really think you'll notice speed differences and therefore want a PCIe-M.2, buy the ADATA SX8200 Pro.

Upgrade your RAM to 3200-CL16 G.Skill Ripjaws V.

Also, use geizhals.de for price comparison since you're in GER anyway.