You will only lose a SATA port if you get a SATA M2 drive. If you get a NVMe M2 drive you will keep all of the SATA ports.Thanks for the clarifications, I think I'm starting to understand it a bit better now. If I'm going to get a M2 drive, I will lose perhaps a SATA port, but am using at max 3 of those I think (one for my old DVD burner, and 2 for my current old hard drived).
Just a few minutes ago just went for it and ordered:
New MOBO: ASRock B450M Pro4-F
New APU: AMD - Ryzen 5 2400G 3.6 GHz Quad-Core Processor
New RAM: G.Skill - Ripjaws V Series 16 GB (2 x 8 GB) DDR4-3200 Memory
And just to avoid any problems, also a new PSU:
Seasonic Focus Gold 450
Once I get all the stuff, and have my desktop running again, will definitely look into a new harddrive, especially into that Samsung Evo Plus
Again thanks for all the advice.