Done the 3M kit a few years back and sealed it with G1 or G3 I can't remember which. Gradually the cloudiness came back.
A few months ago, I smeared autosol over the headlights, left for a few minutes and then rubbed it off. The results were great, didn't use sealant this time, just wax. Wish I did it before going to the extremes of the 3M kit tbh.