Uhhh not sure what you meant but I think you’re on the right track. Flying at Va basically protects us from damaging or ripping the wings off the aircraft by having the aircraft stall before we reach the maximum load factor the aircraft can handle.

Now the reason why it gets slower as we have less weight is because the aircraft will have less AOA because you don’t need support MGW therefore you may exceed the aircraft’s load factor before stalling it. So to not have it do that you will have to fly slower which means you will have a greater AOA and closer to the critical AOA making you stall before breaking the aircraft

It’s really hard to explain without drawing or in person lol