You have p much missed the facts that 1) Davesprite/Jade didn’t work out because of Davesprite’s anxiety over being seen as a fake (with Dave pointing out that he wouldn’t dump her like Davesprite) and 2) self-absorbed, egoistical Karkat at the age of 13 is different from the one in the dreambubble and the eye reveal scenes (where he prioritizes Terezi’s well-being over his own). You ignore that people need time to grow up into being able to handle a relationship, Crusty, and you need a reread.