Well, purple isn’t the best for a mono 4* team based on the vanilla heroes, or even Atlantis. I don’t memorize S3 and event purple 4’s, so maybe someone else can weigh in there.
If you’re okay using multiples having at least 2 Tiburtus would be good. Maybe something like:
Rigard, Tiburtus, Cyprian, Tiburtus, Sabina
If you don’t want repeats Ameonna has massive tile damage. Even if she dies you get her tile damage boost. If she lives and hits with defense down from Tiburtus, it’ll hurt them. Two healers may help keep her alive. My Ameonna is talented up and a damage beast.
Sabina, Tiburtus, Cyprian, Rigard, Ameonna
Two healers adds survivability and Cyprian allows passive damage, so it can work for sure. Is this for raids, provinces, war?
Good luck, let us know how it goes!