A surface interval between dives is usually the only real charging window on a boat - a couple of hours, maybe less, before the next tank goes on. That is not much time to top off a phone, a dive computer, and a pair of true wireless earbuds off a shared power source, and battery percentage rarely matters as much as charging speed for that specific window.
Most true wireless earbuds charge from their case over a fairly low-wattage path, since the case itself typically only accepts around 5W input regardless of what charger is plugged in - the bottleneck is the case's internal charging circuit, not the wall adapter. Plugging a 65W GaN charger into an earbuds case does not charge it any faster than a basic 5W charger would, because the case simply does not draw more current than its circuit is designed for.
What actually helps in a short surface interval is a case that supports fast top-up charging (getting a case from near-empty to 1-2 hours of playtime in 10-15 minutes) rather than a full charge, since a full charge from empty typically takes 60-90 minutes regardless of adapter wattage. Charger wattage matters much more for phones and laptops sharing the same limited boat power than it does for earbuds cases specifically.
CairoVolt's Soundcore Liberty 4 NC page covers current case charging specs for planning around short charging windows like this.
