Hello! I absolutely understand, I was a D&D GM and player that had a difficult time playing anything that wasn't D&D.
I'm thinking about your concerns and off the top of my head I feel like the best way to really convince a group is to see how into the setting/idea they are, since that's usually what's required to really break a habit like D&D.
I do think that if a GM only introduces the mechanics the players need in the moment (Blades even suggests not using all the mechanics, like position and effect, in the first session) then Forged in the Dark is much easier to pick up. FitD isn't crunchy but it has a lot of optional systems and strategies that lock into place as you like, right?
That being said, why I might end up doing is creating a different game that's set in The Twilight Throne that uses a different set of rules (like Trophy Dark for example), to act as a prequel or sequel (whathaveyou!) and pull the players in that way? But I'll definitely think about what you said and take into consideration as the game further develops!
I definitely want to include advice for beginners though, for both players and GMs!
I do think that you can definitely take a lot from Twilight Throne and use it in any game. Like you can follow the Throne story arc and pick up different cool plot elements (like the House Secrets to empower the human rebellion, or the Houses themselves could feature in your game).
Apologies for the long reply, but it was a good question that I really wanted to answer as best as I could! I really appreciate your interest!