Did you not see The Batman? I was stunned because my expectations were low.

Heat gun, careful slow movements with a dremmel, or soldering iron to melt the plastic away. That motherboard can probably handle a flathead screwdriver as a wedge to unglue without snapping apart, though I appreciate your carefulness in avoiding a nuclear Holocaust.

If you have access to a heat gun, I'd give it a shot, especially because the battery needs to be removed too. My other suggestions are not the best for removing a battery, though you might be able to get a good angle to wedge the battery off without stretching the components in the battery.

Consider draining the speaker battery first. I wouldn't bother, but if you are really worried about breaking the thing it's worth a shot.

I've taken apart many consumer electronics in my day, and (anecdotally) batteries have not been an issue. I'd say that you are more likely to snap a wire off one of the components or something quite mundane.