Hi Jane Bad luck and misfortune are similar in meaning, so you don't need both. ''If she had not been so unlucky, she could have done better" "If she had not had such bad luck she could have done better" "She could have done better, but for her misfortune" "She could have done better, but she was unfortunate" "If it was not for her misfortune, she could have done better"

She could have done better if not for her misfortunate bad luck.