The causation runs the other way round from what people assume. Assessments follow market values on a cycle, so a rising market produces higher assessments, not the reverse. A reassessment year redistributes the tax burden across property owners, and your bill can move even when the city's total levy has not, because your home's value moved differently from the average.
Where taxes do reach the price is affordability. A buyer qualifying for a mortgage has property taxes counted in the debt service ratios alongside heating costs, so a high annual tax bill reduces the mortgage that same buyer can carry. That is a real effect on the pool of people who can bid, particularly at the entry level.
If you think your assessment is wrong, the route is an appeal to the Board of Revision inside the notice period, not a conversation with an agent. What an assessment cannot do is tell you what your house is worth today, because it cannot see a finished basement or a renovation done without a permit. Joel Dyck's hand-reviewed valuation can.