Godot absolute force to rigidbody relative force

snippet.cs

var upThrust = 1;
var forwardThrust = 2;

var absoluteForce = new Vector3 ( 0, upThrust, forwardThrust );

var relativeForce = absoluteForce * Basis.Transposed(); //The magic BS that makes it work

ApplyCentralForce( relativeForce );

//I fought with ChatGPT, Bard, and google search for quite some time to get this answer.
//You're welcome.
// btw 3x3 matrices are trash, and 4x4 matrices are where its at. guess what godot uses for "Basis"....