I hope I'm getting this right, as it's kind of both a suggestion for the mod by itself and a quirk with the Cosmetic Armor mod...

The new armor physics resistance effect, which reduces bounce, is a nice touch, but it would be neat if it could be on a toggle, or perhaps a slider.

The part where Cosmetic Armor comes in, and part of the reason I'm suggesting the toggle/slider, is that the bounce reduction still takes effect if the armor's invisible, if the armor's in the main slot.

Testing in a world with just the Gender mod and cosmetic armor, 1.18.2, Forge 40.1.0:

-Diamond armor in main slot, cosmetic slot empty, armor visible: No bounce
-Diamond armor in main slot, cosmetic slot empty, armor invisible: No bounce
-Main slot empty, diamond armor in cosmetic slot, armor visible: No bounce
-Main slot empty, diamond armor in cosmetic slot, armor invisible: Bounce

Further testing:

-Diamond armor in main slot, leather armor in cosmetic slot, armor visible: No bounce
-Leather armor in main slot, diamond armor in cosmetic slot, armor invisible: Leather level of bouncing

Also in Forge 40.1.31

...minor note, if such a toggle/slider is added, and/or this mod interaction quirk fixed, it would be nice if it made it to the 1.18 version of the mod as well as the upcoming 1.19 version. >w>

I have encountered a similar issue in 1.19.2: even with breast physics enabled, there is no movement regardless of if the chestplate is visible or not. Probably a separate issue and I will file a report for it