I have not seen Trigun but I know it is definitely not for children. Back in the days it was easy to think 'cartoons' are for children and there are people who still see anime in that light.

The girl who leapt through time was a real brain banger🤣. I recall searching through the internet so some interpretation to the ending that would fill the void of the opportunity they both lost. In the end it was all wasted time since she did not understand her feelings until it was too late.

Hotarubi is has a similar feel of the passage of time and choosing what's important. Equally sad but bittersweet.

Orange is also nice and thought provoking but it had those sad elements about how little choices influence life paths.

All good recommendations. I tend to go overboard when it comes to anime commentary😆