If I was president of SL/SOM I'd give khat 10 years, and every year I’d take 10% of it away, then the 10th and final year ban khat and make it completely illegal.
I will start a massive employment campaign. Give these people hope and dreams of a better future so that they don’t need to waste their time chewing Khat. Also extra-curricular activities/internships/volunteering for the young so they don’t start. Start with rehab as well and educating the youth
Khat is not something you can take away immediately, Afweyn Barre tried in the 80s and failed miserably. There are people who depend on it for work. you have to give the farmers time.