my BAD dm won't let me play hombrew

It's just a homebrew race and it's not op! it's three kobolds in a trenchcoat which is HILARIOUS. They have advantage in wisdom and dex saves proficiency in sneak and sleight of hand, also they can take 3 actions because it's three characters at once. But they have disadvantage at deception checks to convince people they aren't three kobolds (which is HILARIOUS) My dm says this is to strong but??? A good DM would rise to the challenge and just get better at DMing. Clearly they're afraid to just get better at the game.