I would add a layer of what I call “Return to Sender” in the shield, if the shield is attacked maliciously, have it unaffacted and reflect back the agression to the giver. I think this is also called mirror shields, and you can picture the sgield with a mirrored surface if that helps.
I don’t see why you couldn’t use the sword analogy, sometimes it’s helpful to pull inspiration from what work in the physical, but remember this is not the physical so you’re not limited to only that, make it a lightsaber for example. I usually skip the weapons thing and just picture them burning up from inside.
I posted about what I do here and there’s a link to a movie clip with a visual that can help. Need help - #32 by Mulberry