A confirmed sale also strengthens your position once you start shopping, because a firm offer backed by real proceeds is more attractive to another seller than an offer still conditional on your own home selling.
The tradeoff is a possible gap between your sale possession and finding your next home, which a longer negotiated possession date or a short-term rent-back can bridge without forcing a rushed purchase decision.
In a market this tight, selling first usually costs less in scheduling risk than it gains in negotiating strength. Get your hand-reviewed valuation from Joel Dyck.