Quitting is the easiest situation and the one most often fumbled, because the honest reason is usually a complaint and complaints are what interviewers listen hardest for. Three versions cover almost everyone.
You left because there was no room to grow. Make it about the shape of the organisation, not about being overlooked. The next step did not exist, the team was small and stable, the scope of the role was fixed. That is a structural fact and it invites no follow up. "I was passed over twice" invites several.
You left for better pay. Money is a legitimate reason and pretending otherwise reads as evasive. Lead with the scope and the responsibility, and let compensation sit as one honest factor rather than the headline. Never write a number in an application form field.
You left because of management or culture. The reason is legitimate, the vocabulary is dangerous. Translate the experience into structure: a change in leadership, a shift in how decisions were made, a way of working that stopped fitting how you do your best work. Describe the mismatch, never the person, and never use the word toxic in the answer itself. You have no way to prove the story and the interviewer has no way to check it, so the only thing they can assess is how you speak about people who are not in the room.