@India4 to answer your questions...
Have all taking Mounjaro experienced severe side effects? No, of course all of those people taking Mounjaro who post here have not had severe side effects! That would be quite alarming if it were the case. About 1 in 10 people taking Mounjaro get mild to moderate side effects, usually gastric, temporary and treatable.
Do they diminish within a few weeks? Gastric systems usually go within a few days. It isn't normal to have difficult side effects for weeks and weeks without addressing them. You could reduce your dose, change what and how you eat, use OTC treatments etc.
Which foods are to be avoided? It's not like Orlistat where you have to avoid fatty foods for fear of unpleasant side effects. But most people find they naturally want to eat a lower carb, higher protein diet that includes lots of veg and fruit. Eating lots of processed carbs, fatty foods and sugar might lead to gastric upset of various types.
Is anyone on here using a “Maintenance” dose & if so are you managing to keep the lost weight off? I'm not at the maintenance stage yet, but there is a thread about that in this section which you can probably find, where you can read how people who are at that stage are getting on.