Help me decide: Powerslave or Somewhere In Time for a 10 year old's first Maiden album

My nephew turns 10 next month and to mark this milestone I want to introduce him to some music.

I was gonna go with Megadeth originally but their music doesn't seem very accessible on vinyl so I've opted for Maiden instead.

As per the title, I'm trying to decide on buying either Powerslave or Somewhere In Time.

I've narrowed it down to these two albums because they are very consistent throughout, the songs generally don't drag on too much unlike Maiden's latter work and both albums have amazing cover art which will undoubtedly look great on vinyl + be visually appealing to a kid.

According to his mother, my nephew isn't really into the subjects of Ancient Egypt (Powerslave) or Sci-Fi (Somewhere In Time) but he does like anime and Japanese pop culture.

For me, this feels like a missed opportunity due to the existence of Senjutsu but that would be a terrible introduction to Maiden and music in general IMO due to how long and meandering the songs are - kids like cool things with a lot of energy which Powerslave and Somewhere In Time have in abundance.

Anyway, please help me decide!

Thank you.