Again, the "how did we got here?" structure is a sign of huge pacing issues. And it's not the only problem. Dnf 30%.

Tell, never show, except sometime show, but then absolutely also tell right there.

Suspension of disbelief, what's that? The protagonists want a dog, pouf! A genius dog appears.
Let's go rowing, yay! And in the 50s, nobody even asks if the beginner knows how to swim. Even if a lot less people knew how to swim than now.

Among other things. The last one for me was a bad guy explaining excruciatingly one of the main character's origin, with no reason whatsoever to do so.

I cannot care anymore.