@rbeddoe’s suggestions are good ones. But with a shape like that it’s going to be particularly difficult to achieve a clean surface on all faces. It looks like you’re already using a sensible orientation (one of the vertices facing down), and have played with support density (have you found there’s less goop if you reduce support density? What happens if you go the opposite direction and pack in more supports, perhaps with smaller touchpoints?). Height above base is another knob worth adjusting.
If nothing else works, you could try a completely custom supporting structure (e.g. model in thin, sacrificial fins that stick out from the downward-facing edges and break off after the print).
If you think it’s a resin flow issue, a double-shield as shown here is also something I’d definitely give a try: