I wonder if they could use a material that would "dry" or "freeze" in the shape of the bubble. Maybe harden from the UV.

If the James Webb telescope gives a reasonable indication for the amount of stuff floating around these Lagrange points, it would be popped around once per month [1]!

1. Four hits after 5 months: https://www.theatlantic.com/science/archive/2022/06/james-we...