Not an expert in any of that, but I think overall impact may be greater if people with sufficient means take a more hands-on approach that grants visibility of where money is going. I lean environmentalist be the truth is that there’s a good deal of well-marketed snake oil in the environmental space.

The issue with quibbling over impact is my experience is that people end up doing neither. I recently started a Master's in ecology so I don't have a good idea of what's cost effective right now but I know the field is pretty shockingly underfunded (both for general research and conservation projects). I learned the "fun" fact recently that bird populations in the US are down ~30% in the last 55 years.