I was thinking about that the other day. It must have been a hard sell to get that 90 minute episode in. It makes sense, to anchor the characters to their mother and provide a driving motivation to them, without giving the viewers a bait and switch.

The justification here is probably just that "wow, look how popular Oshi no Ko was, let's do what they did".

Total War is probably the deep end.

I'd direct you towards XCOM 2 or Troubleshooter: Abandoned Children instead. These are more tactics games, rather than strategy.

You might also try Against the Storm or Starsector.

Ancient Magus Bride S2

Oshi no Ko

Skip and Loafer

Insomniacs After School

The Dangers in My Heart