This is a decorator switchplate cover, with enough space for large sliders. If you want to use smart bulbs and ensure that the bulbs are always powered (so that the smart features always work), you'll want to either change the wiring (lots of reasons why you wouldn't want to do this) or cover up the switches. This just screw on over the existing light switch plate using the same screws.
I tried a few models I found around the web, but the best model still had sharp corners and was only for rocker-type switches. I have slider switches I want to cover, and these have the space to fit a bigger switch underneath. Also, none of the models were designed to be printed in an orientation amenable to countersinking the mount screw, which looks more attractive. Unfortunately, after I printed these I realized I didn't quite match the design language of normal switchplates, so maybe the next person to feel unsatisfied with these covers will incorporate that in the next iteration.
I recommend printing in PETG so that tightening the screws causes it to bend instead of break.
I included a photo of the supports I use when printing. The entire top surface is bridged. The model in the photo was sliced with 0.2mm layer height and printed in PETG. With 0.2mm support separation, they should detach easily.