I should connect all those pads/via under the NRF52840 to GND, right?

[Mitch996]

Those vias are not there to provide fixation but proper grounding, right? Because I just connected them all to GND.

Would be embarrassing if they shouldn't.

[Sigurd]

Hi,

Only the 4x4 center vias should be connected to center-pad and ground. See the figures here.

[Mitch996]

Hello Sigurd, the 4X4 = 16 vias are exactly what I was talking about. Since I only have like 2 layers, I'll connect it to the GND, I have no other layer to connect to.