I made this light switch guard that prevents you from turning on/off a light switch. I made the design using 1/5" material, so I’m not sure how well thinner materials would work.
I used .05 acrylic (intended as replacement picture frame glass) from THD. The holes are just the size of the threads so the screws don’t appear to be proud of the plate, and it’s virtually invisible.
One wall of my living room has switched outlets as there is no overhead lighting, but I have many things plugged in besides lights (plus all my lighting is automated anyway). It should have been wired so only one of the two receptacles on each outlet is switched, but they didn’t bother when they remodeled.
that requires some rewiring to create a permanently on (non-existent) switch. for most people, it’s probably much safer to either create the new plate that can’t be switched or an adapter to go with the plate that blocks it.