Book about killer toy robots, Babylon golems, grandfather fakes his death to let the main character get away

Question

It was about these tiny killer robots trying to kill this boy, and his gramps came and dragged him into this weird journey.

I'm gonna talk about spoilers here, gramps has to fake his death so the son can get away, he go find his gramps' friend, who ends up being impersonated by one of the bad guys. Then it bring in stories about Babylon golems, close to the end of the book there’s this sudden chase where the son is on a quickly growing golem. Book ends with the kid using the toy robot’s magical powers to knock down a bully.

Also there was a child with the villains, she straight-up dies. I remember it was some dude’s first ever book.

The cover looked like a creepy snowy street bridge, with little foot prints.

Answer 1

Monstrous Devices (2018) by Damien Love.

On a winter's day in a British town, twelve-year-old Alex receives a package in the mail: an old tin robot from his grandfather. "This one is special," says the enclosed note, and when strange events start occurring around him, Alex suspects this small toy is more than special; it might be deadly.

Right as things get out of hand, Alex's grandfather arrives, pulling him away from an attack--and his otherwise humdrum world of friends, bullies, and homework--and into the macabre magic of an ancient family feud. Together, the duo flees across snowy Europe, unravelling the riddle of the little robot while trying to outwit relentless assassins of the human and mechanical kind.

Found with a search for site:goodreads.com novel tiny golems toys