I think it can be a combination of things gone wrong can take it from "a little gamey" to untolerable.

Bad shots that let it run live or other wise saturate the meat with adrenaline. I just don't think this can be fixed by marinating or anything else.

Trim off all the fat.

Assuming everything else is at least addressed in a reasonable manner I've never had any gamey taste at all. It still taste like venison but none of that bitter or at least that's what I call gamey taste.

Many times I've cooked a neck roast from one like this in a crock pot and cooked just like beef most people can't tell it from beef even when both are right there at the table.

Steaks still taste like venison but I don't do a thing different to them than I do to beef steaks.