How do I decide what title to use on LinkedIn — Senior PM, Staff PM, or Product Leader?

It depends on what you're targeting and where you're getting traction. "Product Leader" is often the most flexible — it doesn't box you in by level, and companies with different leveling systems won't disqualify you. That said, if you're targeting companies where "Staff" is a recognized and respected level, it may signal more seniority. Test a title, evaluate recruiter response over two weeks, and adjust based on data rather than assumption.