Brakes are weak, looking for suggestions

I am not getting good clamping force.

The design seems to be the main problem. You can see the line of tension is not aligned to the brakes’ line of pull, this is evident in the first picture.

I can try shortening the V-brake cable connection point, it is pretty far from the brake assembly and there is room to shorten it without it interfering with the center post. But this wouldn’t change the alignment forces much.

I know I can also get different types of pads, such as crystal pads which I’ve read about, which might help.

It seems like the right fix is to improve the design, and somehow weld or attach the brake line end-point closer to the rear brake assembly as shown in the last picture. This would better align the pulling force with the brakes and should increase the clamping force.

I don’t have a way to weld at my house and am not familiar enough with aftermarket parts to relocate the brake line end-point.

Any suggestions?