AITA for telling my friend to break up with their partner?

So I have this friend, I'll call them Lenny, and they have a partner which I’ll call James. I’ve known this friend for while now now and knew they had a bf for about 5 months.

Recently (around 2 weeks ago) as we’ve gotten closer they’ve been telling me more about their life and Lenny started complaining to me about their boyfriend James. Lenny complained about James joining a discord server they were both in and picking a role that said “single”, then James got mad at Lenny for bringing it up and not believing it was an accident as James claimed it was. Then Lenny also told me that James frequently switched between tiktok amidst their text arguments and Lenny told me it annoyed them because it felt like he didn’t care or was not taking it seriously in a way.

After another argument ~1 week ago where James didn’t read anything Lenny had taken time to send him because he “forgot” and (allegedly) still didn’t read them, I suggested it might be good to consider a break up, as Lenny seemed very annoyed with James and after all the arguments Lenny had told me about I thought it was a fair thing to suggest. After James was actively ignoring Lenny whilst they were arguing (which is a thing Lenny has openly stated they hate) Lenny ended up going through with the break up. Note: This was not me forcing them at all, I only suggested it.

However, about a week later James was suddenly talking a lot more and acting more affectionate now that they’d broken up, (which sent a lot of red flags for me) after talking they decided to get back together. I said it probably wasn’t a good idea considering everything Lenny told me but they did it anyway and I didn't stop them.

After a few days, Lenny complained again about James not replying to them properly and somewhat ignoring them again despite them having a conversation about not liking being ignored many times in the past. I said I had a feeling something like this might happen and then Lenny went on to say how it felt like they both just didn’t really care anymore and they felt a lot different to how they did a few months ago about the relationship.

It is worth it to mention I also have feelings for Lenny but I am trying to not let that get in the way of my reasoning.

When I said I didn’t think this was a healthy relationship, Lenny said they don’t think they’ll break up with James again because he’d probably go back to what he did last time and suddenly start talking a lot again and asking for Lenny back. Lenny also said they do genuinely love James but he annoys them with all the things he does

I have suggested to Lenny to weigh out everything and consider whether everything they love about James is worth it to stay with him. I don’t want to be trying to ruin a perfect relationship but Lenny has expressed feelings of being under appreciated and such and I don’t see it as a good relationship.

So am I the asshole? Am I letting my feelings get in the way or is it a valid thing to tell my friend to break up?