I think it had its cake and then didnt eat it. I don’t think it was a romcom as the characters dont get together in the end. The manic pixie dream girl is a problematic trope not because of character quirks but because the woman is just there as part of the man’s story, to fulfil the man’s needs, with no depth of characterisation or needs of their own. This was the exact opposite of that, the Tom character wanted summer to play the mpdg role in his life, she wanted none of that as she was her own person with completely different priorities, the film was anti the mpdg trope