Encouraging Creative Play

Anybody else ever feel like your players rarely surprise you? My players are lovely people and great at role-playing. But when it comes to the mechanics of gameplay and the plot of the story, most of the time they just let events happen to them and take the most obvious path forward, even if it's a slog or not ideal.

Here are some of the things I do already:

Varied, multi-level terrain. Environmental hazards. Interactive elements. Have the NPCs interact with the terrain to reasonable success. Multiple objectives beyond beat up the bags of HP.

Situations with competing priorities. Moral hazards. Loads of magic items that aren't just combat enhancements. Handing out inspiration.

Straight up telling them, "Hey, by the way, the murder mystery was fun, but I felt like you guys could've come to a conclusion faster and better. (And their conclusion was wrong and, given the circumstances, I couldn't fudge it to make it right). Here's a few examples of how you could have solved the problem in half a session using some basic tools." (I wasn't trying to stunt on them, they were asking me what I am like as a player, and I told them I'm a wild card, and gave the above as an example)

So, I'm wondering what you all have done to foster more creativity in your players that I haven't covered above.