
Veramood was a great male lead during the story when all the struggles were afoot. When the king was alive, Seri was poisoned, and so on.
But what is going on now? He's behaving like a complete asshole. I liked him for Seri because it felt he was her equal and respected her. Now he's almost one of those abusive partners that tell you who to meet, what to wear, who to talk to and what not. Dear lord.

Why the heck is there softcore tentacle H in my magical school Shoujo

It is. It slowly starts to feel like a Shoujo written for men than for women, especially with the Yuri elements but no tag for it, and the love interests being so obnoxious there.
I still hold out hope that they go the Yuri route for Elizabeth and Karen, and this octopus thing is just a weird outlier.
If there's a novel to it, please drop a link