If you are selling within a year of buying, talk to an accountant before you list, not after you accept an offer. Exemptions exist for death, disability, a job relocation, a divorce or separation, and a few other listed life events, and applying one correctly depends on documentation, not timing.
Most downsizers selling a long-held family home are nowhere near this rule, since it targets speculative flips, not a home owned for years or decades. If your purchase and sale both fall inside the same calendar year, get ahead of it with your accountant rather than guessing at the tax outcome.
Joel Dyck coordinates the listing timeline with your accountant when a tax question like this is in play. Get your hand-reviewed valuation from Joel Dyck.