How to make characters feet always face an object?

Hello. I’m looking to try and make a small 3d world with its own gravity. I’ve managed to make my own gravity by applying force but I am having trouble getting my character to rotate to have its feet always on the planet so that the vector going through its body, I guess its UP vector is always pointing UP (away from) from that position on the planet. I’ve tried doing subtractiong of the planets centre and vector position to get direction but my knowledge of vector maths isn’t really that great. Does anyone know how I might accomplish this or what calculations I need to do? Any help greatly appreciated.

Maybe line trace in negativ up direction (down) and set the player Rotation to the hit impact normal by making rot from z(?).