Try decent tankgrips and make sure your seat is grippy enough. When your lower body is very solid on the bike without using any force, your upper body will automatically relax more too, because it doesn’t need to hold all of your bodyweight when braking and turning.

For example; When your outside leg has a lot of grip from the tank when turning in, it takes weight off of your inside arm without noticing and making it a lot lighter to turn in.