Recently, I've grown quite close to a girl I know through a friend. Unfortunately, I discovered that she has a boyfriend. She mentioned that their relationship is unstable, and she doesn't see him as marriage material. Upon learning about her relationship status, I initially attempted to distance myself. However, she unexpectedly came closer, and make it quite clear that she's interested in me but hesitant because she feels she doesn't know me well enough yet.

should I go for it or give up?

seriously, this girl also not a good target. If she can do it to the "current" boyfriend, she can also do that to you next time...

Girls like this are opportunistic. Always looking out for better opportunities while stringing along their current bfs.

If you be with her, she will appear to be happy with you while finding your replacement.

I despise people who don't end relationships until they find a replacement.

Not everyone believes in your worldview of use and be used. It is a sad worldview.

She told me her boyfriend does not treat her well. But I can't figure out why she hasn't broken up with him if that's the case.

I’m a poorfag bro… I just bought 256Gb of iPhone 15 Pro and 15 Pro Max (for inflight delivery) which officially categorises me as poorfag.

Not denying and totally agree. But like food, water, security, sex is a primal and biological need. Some would even say, animalistic. As modern humang beings. surely there are things beyond sex to give meaning in life no?

Not saying I don't enjoy sex. Different people find meaning in different ways.

Let's not derail the topic to a philosophical discourse. TS needs help 

There are things beyond basic needs that give meaning without being transactional.

But let's address Wacky's question. If it is transactional, it is not love. I am not denying most relationships are transactional. That is all too common.

But not all. The thing is, some would want to find that love, however hard it may be. Also, some other guy mentioned the other day, your partner may be transactional, but you don't have to play the game. For me, if I know the women is transactional, then off she goes. I will not show off my wealth to attract women. I drove my pleve to go after my wife. She was there when I was poor. After so many years of hard work and trying so many businesses, she is still here with me even though I am still poor.

So they are rare, but they are there. Just have to look harder.

For those who are transactional to you, you can be transactional to them. I have no issues with that, the question to TS is what is he looking for.

Common doesn't mean right. Well I'm just jabbing your apa sarahan joke, but in all seriousness it's still up to TS to decide his own moral compass.
My 2 cents as a lady POV in a relationship:
I enjoy being pampered and it's easy for me to demand more over time, or that he does less over time. Basically, either side may take one for granted. I try to remind myself to be grateful for his gestures and to return with affection/appreciation/my own side of gestures.

Now the question is, did he take her for granted, or she took him for granted? It's very subjective and vague to hear only her side of story and even that can be lies, so you'll need to observe more or, ironically, hang out with her more to learn more about her. I think hanging out as friends is fine, but of course there's also emotional cheating you'll have to consider. Don't be surprised if the bf confronts you one day.

Lastly, I think people stay in relationship (even when it's already broken/toxic) is because it's already the comfort zone, change is often difficult... It sounds like she's looking for you to be her next comfort zone. I don't know if it's a good thing -- I generally believe in slowly building up / fixing a relationship, breaking up would be the last resort. Idk if she tried enough yet.
Interesting view - I agree that romantic love includes give-and-take / to love and be loved, but I prefer not to call it transactional as I think it gives a feeling of rigidity, as if you need a balance sheet to track how much you're getting or giving. Romantic relationship is a partnership/codependency where both sides does something for each other.

Eh did I say something otherwise?