Stan was already in a really good spot for that though. The rework specifically made him an incel and even more of a loser to start. He was originally much more like Holly; a low confidence, nerdy character that the foundation was being laid for a glow up in the same way that Holly has been receiving. The conflict between him and Louise was much more subdued, and Louise thought of him as more of a slob than an outright creep. I forget if it was a life drawing event or a concert, but Lena could invite Stan and when he showed up with a fedora and a trench coat she said she would work with him on it after he said he thought he looked cool.
What? Lena can give him a chance and kiss him. Following that plotline, he shapes up and they end up fucking.
I've said this many times before, Stan's rework was a net negative in my opinion. Perhaps others like incel Stan more, but I found him much more interesting in that early development phase. It felt like he had way more possibility as a character then, than he does now. Perhaps if Lena is on Stan's romantic path a lot of those possibilities could still manifest. But the other interesting aspect of Stan's early character was that it felt like Lena could still help Stan, as a friend, without having to be a romantic interest.