So I am studying a game I played where I encountered a setup I’ve never seen. They identified it as the Dutch defense. Which I know of, but I’m not at all an expert. I’ve only really studied the Scandinavian defense and the London because I want a base to learn from, but I need to work on my principles more than lines. 

That being the context here is where the analysis tool thinks I should have deviated 

I continue the London, and play Nd2. If you use lichess and turn it up a bit it wants me to play h4. I included where the position ends up. Which the computer tells me is even, but when I play Nd2 black gains an edge, and as the game moves it balloons to almost -1.3 until he plays this move, where it moves back to my favor. In the game he resigned, which is nuts to me.

So I give all this explanation to say my take away here is the computer says I should deviate, but I don’t feel like I “abandoned” principled chess by playing the moves I did. Because I wanted to get my setup and then attack what felt like an open king side after the center resolves (I would have played exf5 (after a long time thinking, which might be why they left?) if the player didn’t resign. What take away a would you all gather from a game like this, and how would you analyze it? I’m happy to provide the game link (or the move list) if people want, or you can look me up on chess.com and see my history. 

Thanks in advance!

Opening deviation (London)