AU Luke ends up at Bespin with Han and Leia who are flirting but still fighting a lot, and Luke is angsting because he loves Han but it's clearly not gonna happen.

Lando flirts with Luke a lot, but it causes issues between Lando and Han. Han gets super jealous and starts acting like a dick to everyone.

Luke is at first afraid because he thinks he's done something wrong, like maybe Han thinks he's deliberately encouraging Lando's flirting (and it takes Luke fucking ages to realise Lando's even flirting maybe).

Leia is alarmed by how badly Han is taking things. She tries to talk some sense into Han, saying that Han is clearly deeply in love with Luke, and maybe he's not addressed/gone for it because he's afraid of its intensity. And it is VERY intense.

Unfortunately, Luke is kidnapped by Vader (who is sidetracked by Lando away from Han and Leia). Han is now absolutely furious at Lando, who feels as guilty as he did in the films, but insists that Vader didn't seem interested in killing or torturing Luke. In fact, Vader nearly killed him for even suspecting such a thing.

Han of course does his usual act of dropping everything to rescue Luke, and of course he succeeds and there's a lot of lovin'.