Don’t know if it’s only me, but since a few days ago, the hitbox that allows to resize vertically the layer side bar, is too narrow, making it almost imposible to click.
i came with a kinda dumb workaround:
Open Figma’s console and past this:
document.querySelector('.resizable_panel--bottom--kBKKu').style.height = '16px';
It basically temporarily sets a height to the resizable trigger, and makes it easier to click.