Also i have trying to change weight reduction in inventory, its working same. But it's didnt directly affect base item weigth and should work in inventory as weight reduction in anky inventory. As i know, @AgitoReiKen already create plugin for change weight and another params, and I believe, must be a way to change that param in UI without creating Mod
Player/Dino weight will reflect the weight change but each item will not show a weight change. I have a beta plugin on my discord that can reduce weight, change stack size, limit bp uses and block items from being in player inventories.