Despite the issues with Switch skins back in 2017, modern console and Joy-Con stickers should be perfectly safe to apply (and remove. Now that more companies are aware of the initial problems regarding the finish on the plastics used, they’ve been able to formulate adhesive mixtures that get around the problem. Even Dbrand itself has released a number of skins for the Switch since its earlier failed batches (ones that never saw store shelves, for obvious reasons) that promise not to leave any residue behind if you decide to remove them.
While it’s still recommended that you take some time to look into any adhesive skins — and the companies that make them — before you buy and apply, it shouldn’t be too much of a gamble if you stick with brands you know and trust. Check customer reviews (both positive and negative), look over the item description to see if it specifically mentions being safe to remove, and be wary of anything with a price that seems too good to be true. If you do eventually take off any skins that leave a residue, be sure to clean your Switch off using recommended methods.