Wearing Weighted backpack to progress on Push-ups?

I don't want to do Push-ups variations to progressive overload, I feel like yes they're harder if you turned it into a deficit or handstand push-ups, but they're technically a different exercise now. They either hits different muscles or put emphasis on different muscles than others. I want them to hit the same muscles, same amount but just harder.

Is weighted backpack and vest my only choice? If then what kind of backpack should I choose? Small ones, big ones? How they should he sitting in my back? How to avoid them moving around on my back?