Being the smartest person in a room puts a lot of extra pressure and stress on you. Proving certain kinds of people wrong is hard. Doing it without upsetting them is even harder. After a while you just give up and either stop teaching people making you "toxic because he only cares about himself", or you give up trying to explain properly making you "toxic because he think we should just listen without proper explanations". Only solution is to leave and find smarter coworkers.