No power while cranking

Reads like possible ignition switch.
Its not that hard to test with a meter but... you already bought one.
The switch sends power out to different wires in different positions. It dont take a whole lot of power to activate the starter relay (yellow wire). Starter itself runs on a different/larger wire.
Low voltage into the ignition switch would prevent other circuits from functioning in other switch positions.
Its not uncommon for manually operated switches to fail eventually. Its not uncommon for this models switch connector to harness connector to overheat and melt either.