I'm pretty sure it was meant for young teens and older, despite the tamogatchi origins. If not they respect their younger audiences more than America does. I was 8 when the original show was released and when that skullgreymon episode came out it seemed like an amazing plot point for the story, it taught me that the fear of failing to protect others can cause people to accidentally harm those they meant to protect.

The only reason this isn't bringing people back to the theaters is the prices of seeing movies, and the ease of waiting for streaming platforms to have it. People are realizing that lately it isn't worth going to the theaters when they can wait for streaming services to have it and not have to pay extra for the tickets, drinks/snacks, or travel. Plus it seems more and more movies aren't worth the effort of seeing in theaters anyway as Hollywood has become so afraid of taking chances with storytelling, except in ways that make no sense.

Personally I loved how the manga ended with Historia not sounding very hopeful as you saw the changes over time happen and fighter jets are introduced in the last time age . The finding of the new "titan tree" in a way felt like the hope of trying again to break the cycle, at least in my interpretation. I am very sad though that Mikasa was basically made a simp for Erin in the anime despite her being fairly intelligent and capable of being without him for 5 minutes in the manga. The only other thing I'll comment on is the Erin and Armin conversation, I didn't think it was too fast for Armin to accept because of how much he knew Erin and knew how he thought. Armin is also very intelligent and would have deduced nearly all of the plan without the heart to heart. That just confirmed things at least in my opinion.