So, did some research.
The AM02/Pro is based on the AM03, which in turn is a (HYSTOU, VENOEN, WEIDAN, M6) AMD 3750H based mini pc.
They all share the same mainboard HDF520007-P01, the layout of the AM02/PRO in this regard is VERY similar.
Okay, why is that important? The AM03 has the SATA port and a
5 pin JST 1.25mm molex picoblade connector which provides 5V and GND.
The AM02/Pro has the same SATA port but the base plate covers the 5 pin JST 1.25mm molex picoblade board to wire socket, it is there just covered.
Here a picture of the AM03:
AM03 Mainboard base shot
Here a picture of the AM02/Pro:
AM02/Pro Mainboard base shot
Notice in the AM02/Pro mainboard base shot the tiny beige connector in the left bottom corner? That's the 5 pin JST 1.25mm socket.
I did disassemble the machine
(warning ribbon cable connecting mobo and front IO) and cut the plastic away covering the socket, I did some multimeter magic while the machine was powered on.
The pin out is as following with respective alignment:
[NVME] slot on top
[SATA] facing left side
[ I I . I I ] sata power facing left side
GND GND NC +5V +5V
[RAM] facing viewer
Here a picture of my DIY cable from scraps of several older machines. The Sata power connector was used as a donor.
FYI it is a COMAX model with the top plate removed for DIY soldering prior to assembly.
Crimped power cable JST 1.25mm
In theory something like the DELOCK 85336 power cable should work when recrimped to the JST 1.25mm 5pin connector.
The SATA port is special in that regard, that you will need an angled cable facing away from the alingment notch, like this one from LINDY Art.-Nr. 33350 :
Angled SATA cable
Next step is to model a base with the footprint of the AM02/Pro and the frame of a 2,5" sata ssd.
I will model that base, probably a bit deeper than the original base of an AM03 to provide more airflow and comfortable wire routing, once I have a prototype I will post that STL file for whoever wants to embed a 2,5" sata ssd into his AM02/Pro.