You know, as someone who used to not give a fuck about the ships and would ship and shit on every pairing in the show, it's pretty weird for me to actually want kelly and marco to be endgame. It's not that I specifically like kelly with marco, but at this point the star/marco dynamic that used to be the entire reason I liked this show has been nuked out of existence, to the point that alfonzo and ferguson seemed to chime better with marco in the last earth episode.
Star's been the entire reason that marco is still in the shitter he's in currently. He came back to find himself absolutely unwelcomed and tried to leave, but star chained him up and sat him down like a dog. He forgoed his chance to be an ACTUAL squire, and in the very next episode he was shat on for it. He then tried to make up for it by playing their game, showing actual development in what seems to be marco's time for character development, instead he was shouted down and ran back into his kennel under a stack of boxes.
Sure, he may be ignorant of the ways of mewni, but at least he tried to set her down into life on earth, whereas for marco he was basically on his own, star showed zero empathy for him. She had zero care of his emotions and wellbeing, locking him up in the depths of the castle then bringing him to the beach with her bf when she knows perfectly well he's still in love with her, immediately followed by asking for his eternal protection in an entirely forced way, completely spontaneous, all the while the memory of her being a complete asshole to him minutes before lingers in the minds of the viewer. 1/2