I think you'd be cutting it close for the water taxi. IME, it takes about 25 minutes to get downtown. Everything would have to go perfectly for you to make it.
As a alternative that would allow you to relax a little upon arrival, would you consider flying out of BZE? If it's just you, when you add up the cost of the land taxi and the water taxi, it's not that much more expensive.
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Newfoundlanders are the only people in heaven who want to go home.