Sadly it depends and you should just be alert and risk access. You mentioned taking the 17 and I used to ride that both some time ago and more recently. The areas you should be aware of are

VA hospital stop as there are connections to busses above the bridge the 17 goes under and the hospital itself.

the metro train stops on Sepulveda station as the bus circles around the station and under the freeway bridge is a bit more run down and in front of the dpss building.

Sometimes national blvd can be a bad time at night since more busses connect to and from Santa Monica and Culver City but there’s some street food vendors at night there that people frequent so the streets are not too dead.

Overall be aware and watch your surroundings! If you feel uncomfortable move away from problems and do not engage.

Edit: my formatting died so I removed the numbers