In my opinion all these problems arise because you get your companions approval rating too high too fast. During my first two hours in BG3 Lae'zel went from being unfriendly, rude and arrogant to "your scent drives me crazy, I must taste you". Why? Because I interrogated Zorru with her and let her doing it her way. This pushed my approval rating over 20 and started her romance. It felt wierd, out of nowhere and honestly just cringe. There are Lae'zel sex speedruns on youtube in under 4 minutes!
With Karlach I had the same problem. I decided to help her kill the paladins and helped her with her engine. Some - in my opinion - just friendly communication about her backstory let to "I wanna ride you until you see stars". Maybe two hours after I met her.
So far I played maybe 50% of Act 1 (cleared the swamp and the goblin camp) and my approval rating with Gale is already somewhere at 80+. This is insane. All I did were a few things he liked (stepped between the crossbow and the goblin and saved the child in the druid grove) and helped him with his condition. That's apparently enough to nearly max his approval rating mid Act I. Obviously he started flirting with me and I had to shut down his advances two times so far ("Weave"-Scene and at the party in my camp).
Astarion is the same. I let him bite me because I felt like he's in serious trouble because he's too weak to hunt an animal for blood. That's what he said. It was not clear to me that the game views this as a romatic gesture. It feels like everytime I express interest in Astarions backstory and how he became a vampire he misunderstands my curiosity as a romantic/sexual approach. It is wierd and cringe. It sadly feels like a bunch of horny teenagers wrote the companion interactions and the only goal they had in mind was to have sex as fast as possible.
