Should I [20M]be worried about the people my girlfriend [19F] hangs around?

Posting from a spam account. Looking for genuine advice, idk if I’m over thinking too much (i tend to do this) and don’t want to make a problem out of nothing so I wanted to hear other peoples opinion on this. If I’m overthinking please let me know lol but my girlfriends best friends are a bit off

One of them flirts with other guys while in a relationship. Apparently she’s also made some comments about other guys but more about appearances (not as much but still). I found this out through a friend but don’t know how to bring that up.
Her other friends has weird moral around getting with people her friends have a history with. I’ve talked about this with her and she feels weird about her friend doing this.

and then the friends at her job are also a bit weird

one of the girls actively tries to get with this guy even though he’s made it clear he just wanted to be friends with her. My girlfriend even helped her to try and get the guys attention. Now the situation has escalated and the guy is bringing up harassment) She said she’s now trying to convince her to leave the guy alone.
she’s friends with a guy who’s has openly flirted with her. shes came to the conclusion that he’s either flirting with her purposefully even after being told that she has a girlfriend, or he’s flirting to make this other girl at their job that he’s involved with jealous. She has mentioned to him that she as a boyfriend, but she still hangs out and jokes with her.

Shes really oblivious to other people sometimes. And in these situations I try to give advice based on what I think I’d do in these situations (I’ve said I personally wouldn’t be friends with any of them, mentioned the girl harassing the guy is wrong, and also mention that I wouldn’t put up boundaries with these people). I love my girlfriend and trust her, but she seems hesitant to put up any hard boundaries. Like i mentioned earlier she has mention having a boyfriend, she’s told her friend (that harasses that guy at work) that she should move on, and has expressed that she doesn’t like her other friends behavior. But idk, is it weird that she’s around so many people like this? Is she handling this right? She’ll sometimes ask me what to do and I just tell her what I’d do because I never want to tell her to cut anyone off or anything.

TLDR: My girlfriend has some questionable people around her and she doesn’t set hard boundaries with them. Is that weird? Or am I overthinking?