40K for normies is a horrific butchering of the setting though. Dan Abnett stuff is all perfectly in setting, just a more of a gentle slide into it. It was the first 40K book I read, and I remember it still. Yeah, it was just futuristic WWI. And then some one became a demon because a bit of statue got stuck in their flesh. And things slowly ramped up from there. We saw STCs, and corrupted Men of Iron, fighting in a Warp Storm alongside Eldar and an Inquisitor, the Hive City Verrunhive with it's population of billions being besieged by an army of crazy war machines like giant crab bots, climbing spiders, and a giant Spike, a pilgrimage to save the relics of a Saint, and somehow harnessing holy power to banish an armada, going into fighting in floating cities and infiltrating a chaos controlled base, where their chants are causing madness and we can see first hand the cruelty they experience under Chaos. Skip straight silver entirely, and go straight into the finale of protecting the Reborn Saint against the bunch of deadly assassins with their own unique abilities. And likely end it there because it's a really good end point.
Once Dan Abnett gives you a taste of the setting, than you can start getting into the more crazy stuff. But jumping right in will just turn people off, and making it for 'normies' completely butchers the setting.
Mind you, if you do just go fully animated, you might be able to just jump right in. People are a lot more tolerant of crazy stuff in animated productions. In which case I'd likely either do Guard or Ad Mech, fighting against Necrons or Tyranids.
Though I would absolutely love to see a Carmen Sandiago style story featuring Inquisitors trying to hunt down Trazan the Infinite.