I genuinely think this is very pretty! I'm not sure what the canvas is made of (is it cloth? Would it technically be called a canvas?), but it's still very pretty. It reminds me of a painting of a field of flowers.
If you wanna find something to cover them with, maybe a resin? Like, paint the resin over it rather than pour it on. Idk how that'd turn out, but resin is kinda like liquid plastic before it dries I guess? It'd harden and protect whatever was inside. However, IDK how it'd turn out. Maybe do some research online?