There were some great tzaddikim that bought lottery tickets. Not everyone agrees, but certainly Yesh Al Mi Lismoch, so it can’t be totally assur or a P’sul.
Certainly it must have only been occasionally, because Leis Man D’Palig that buying it regularly is a waste of money.
There is a Chassidishe legend about a certain tzaddik who learned and did chessed every minute of the day. Once every few months when funds ran low, he did his ‘Hishtadlus’ by buying a lottery ticket (and winning apparently.) But I think no one today is on that level of bitachon and Melumad Binissim (a Baal Mofes).