The moviemakers are coming with serious cred now, thanks to Chloe Zhou's multiple Oscar wins for Nomadland. So there's reason for optimism; Marvel Studios hasn't stepped wrong with a single project yet (of all their films, only The Incredible Hulk mildly disappointed at the box office.)
Producers at Marvel have learned and stuck to their guns the past couple of decades, over giving an auteur director too much control (ie. Ang Lee's Hulk.) We'll see if Zhou managed to serve her vision and the studios' vision in equal amounts.
This will be the MCU's most 'out there' project since Guardians Of The Galaxy. And it's hard to believe there was a time when everyone was wondering why they were doing that project - barely known characters in a comic series that came and went often. But we know there's a larger purpose to everything Marvel Studios does, in filling out all these corners of their universe.
I was heavily skeptical about Ant-Man, but they did it because the Quantum Realm was going to become hugely significant down the road. Eternals is going to be part of a larger set up, I'm sure.