For a professional-services or trades audience: mostly no. Emoji subject lines pattern-match to promotions, nudging mail toward the promotions tab and lowering the 'a person wrote this' signal that earns opens from business owners.
For consumer lists with a casual brand voice, one emoji can add warmth without damage. The data on emoji lift is genuinely mixed, which itself tells you it's not a lever that matters much either way.
The subject-line levers that DO matter: stating plainly what's inside, front-loading the first 35 characters, and never faking urgency or 'Re:'. Test your lines in our checker. Mechanics first, decoration last.