The WiFi antennas in the GPD Win 2 are poorly placed - located roughly under where one would grip the device with their palms. This results in noticeably degraded performance when holding the… handheld device.
I replaced the stock antennas with a pair of MHF4 antennas and installed them in saner locations.
Red lines mark roughly the location of the original antennas while pink and cyan mark the location of the main and aux antennas respectively.
I don’t have metrics for the old antennas as I did this mod only after accidentally damaging them. However, the new antennas are noticeably better - achieving three bars of strength in spots of my house where the stock antennas reach one to two bars. More importantly, my grip no longer degrades speed nor strength of signal.
Seeing ~500Mbps download/upload when the device is held next to my router and ~180Mbps download/upload in the spots which have the weakest signal.