> digestive problems where food rots in your stomach

I assume you mean gastroparesis - this is an extremely rare side effect

> Bad depression

Again, pretty rare side effect.

If you think these are the minor things I'm confused as to what you think the major side effects are.

Gastroparesis is literally the method of action of GLP1 agonists. It slows gastric motility. Gastroparesis is literally slowed motility of the stomach (where 20% of food stays in your stomach after 4 hours). It doesn't matter why, that is the literal diagnostic criteria, ergo it literally causes gastroparesis.