How to connect the power planes of 2 PCBs with the least stray inductance?
A bank of 8 pins each for power &amp; Gnd like one of these would do it, with 3A (or more) current rating per pin
https://www.digikey.com/products/en/connectors-interconnects/rectangular-connectors-headers-male-pins/314?k=male+header&amp;k=&amp;pkeyword=male+header&amp;sv=0&amp;pv1989=0&amp;pv88=26&amp;pv90=2&amp;pv2024=9&amp;pv91=623&amp;sf=1&amp;FV=ffe0013a&amp;quantity=&amp;ColumnSort=-66&amp;page=1&amp;pageSize=25

Select a suitable female socket to mate it with.
https://www.digikey.com/products/en/connectors-interconnects/rectangular-connectors-headers-receptacles-female-sockets/315?k=female+header&amp;k=&amp;pkeyword=female+header&amp;sv=0&amp;pv1989=0&amp;pv88=32&amp;pv564=2&amp;pv1790=1&amp;pv2172=i2&amp;sf=1&amp;FV=ffe0013b&amp;quantity=&amp;ColumnSort=0&amp;page=1&amp;stock=1&amp;pageSize=25