Not a bad idea. The hardest part I think would be getting the insulation to the right thickness to fit. Not sure how well it cuts.

Most art probably isn’t very thick either, and 2" thick is a sweet spot because it works better at low frequencies, but isn’t excessively large

Examples here

https://www.acoustimac.com/acoustic-panels/acoustic-panels-dmd-series

I’ve done a few with my own photos printed on them, they look like canvas art. Well, they basically are, but also filled with sound deadening insulation.

I will probably make some myself at custom sizes, it’s basically a frame filled with insulation from the big box store, wrapped in fabric.

The impact they have is reducing room reverb, which helps a lot for conversation when there are a lot of people in the room.

Sound panels. They’re insanely effective. I put up a few at home, and now I complain about every place that doesn’t have them.