The beetles and their larvae only eat stems and foliage - the bulbs are unaffected. So no need to dig up and clean or move :-) And the lilies should come back just fine next season.

If the beetles are present in your area, there is not much you can do to deter them. Other than avoid planting lilies :-) Hand picking is the most effective if laborious solution. And there are some insecticides you can use but most will be broad spectrum and affect other, more beneficial insects as well. Neem oil is pretty benign and together with hand picking can reduce larvae as well as deter adult predation.

When hand picking check daily. They fly in in no time. Cup your hand below the beetle before picking it as they drop to the ground instantly when you disturb them. They tend to land upside down ie dark side up so you can't see them. Some years are worse than others.

I find they do affect blooms because the chew on the buds.