The verdict
If you need to coordinate campaigns or projects across several people and Notion is not already your system of record, pick Monday.com. It gives you boards, dashboards and automations from day one.
If your team already keeps its docs, projects and decisions in Notion, pick Notion AI. The agent can read the real project database, which is more useful than a chatbot with a pasted summary.
Be honest about the cost on each side. Notion AI is part of the Business and Enterprise plans, so you pay for moving the whole workspace up a tier. Monday.com costs more as you add seats. For most small teams starting fresh, I'd pick Monday.com.