Yeah, I remember that. The incident with Arenas is a great example of how a stupid thing can ruin a player's career in the NBA. It's worth noting that Arenas was a very capable player, as he averaged 29 points per game in his prime. However, teams lost interest in him after that incident, and he ended his NBA career just two years later. As for Morant, you're right that the league management should suspend him for a longer period of time to discourage him from doing such things in the future.
Regarding Ja Morant's issue and suspension:
"Im going to take some time away to get help and work on learning better methods of dealing with stress and my overall well-being," Morant, who has deactivated his Twitter and Instagram accounts, wrote in a statement to ESPN and The Athletic.
https://www.usatoday.com/story/sports/nba/grizzlies/2023/03/04/grizzles-ja-morant-flashes-gun-instagram-live-nba-investigating/11398803002/On the same article, it has been said that the NBA opened an independent investigation but it wasn't disclosed what will likely happen to Ja and what would be his punishment if he's proven guilty but some people are already speculating that it will lead to a much longer suspension. Poor kid, it doesn't have to be like this if only he wasn't surrounded by wrong people.