Unable to add new skins or delete old ones

I've made a few new skins that I've been wanting to use/add to my collection. When I add a skin or delete a skin, it works/shows up, but once I open the game or close the launcher and reopen it, the skin is no longer saved there, and the ones I deleted are back again.

I’ve tried to solve it via editing the skin, adding multiple at once, and more, but nothing is working, and it gets pretty annoying.