I was reading in the book “The Garden of Peace” by Rav Shalom Arush just this past shabbos that money won gambling is not kosher as one is benefitting from other’s loss.
However this does not include these lotteries that are sold as a pot as you mentioned above. This money is not acquired by other’s losing anything.
The book continued to say that if a person has true emunah he buys one ticket and only one ticket. He knows that if the Ribbono Shel Olam wants him to win then that ticket will have the numbers needed to win.