Thanks to the modern method of welding plastic with hot air with special additives, the edges of the crack are reliably welded together at the molecular level, completely returning the parts to their original rigidity and flexibility, so the bumper will not crack from the slightest vibration after that. If you want to assess the scale of the work in advance, learn about the restoration of internal amplifiers and the technology of delicate local masking of seams without applying thick layers of putty, see the information on https://autobodylab.com/services/bumper-repair/, where professionals clearly demonstrate all the stages of the restoration of elements from any types of thermoplastics. From my own experience, I can say that after such welding, the joint becomes monolithic, and after the final painting and polishing, you will not be able to find where that unfortunate crack was, even with a magnifying glass. Feel free to take the payment from your insurance company, sign up for a quality service, and restore your original bumper — it will last for many more years, maintain the perfect factory body clearances, and delight you with its impeccable appearance!