Arms and legs contort when I apply Ik rig, also automatic weightpainting acting odd

I have modelled a character In blender

With a very simple rig. It has IKs on it.

Every time I apply the rig to the objects that require weight painting some of the objects (like the right knee)

Just decide to destroy themselves as seen here, the knee cap is of course supposed to face the front.I’ve even tried resetting the rotational value of the bones and completely redoing the skeleton 3 times (yes, i’m that persistent)

Not to mention that on the left arm (and on some other models even the left leg) automatically weight paint correctly, but the mirrored bones/meshes for the other arms and legs just flat out don’t work very well. (even though the topology and the bone positions is the exact same, just mirrored.

If anybody can help, that would be absolutely amazing

Oh yeah, here’s an image of the second problem listed

Set the Chain Length of the IK constraint to 2 and play with the Pole Angle.

You can use this script to calculate the perfect pole angle: https://blender.stackexchange.com/questions/19754/how-to-set-calculate-pole-angle-of-ik-constraint-so-the-chain-does-not-move

Also, make sure that the thigh and shin bones do not form a perfect straight line, the knee should be closer on the forward axis to the pole target than the other joints in the leg.

As for the arm, it’s clearly not weighted, do not rely on the automatic weight painting, if you want quality results, you have to do it manually, anyway.

You need to fix weight painting. Also I suggest to delete left part of your mesh and use mirror modifier to keep editing and weightpainting symmetrical.