Here's what's been working for me (and what I used to do in fcp 7 as well.)
I start with my original file [ex. ClownJumps.mov] that is in the timeline in Resolve 14.
1. I output my updated After Effect render and append a "-2" to it. [ex. ClownJump-2]
2. Close Davinci resolve.
3. Then I rename the current working file to "-bak", just in case I want to revert. [ex. ClownJumps-bak]
4. I then I rename the new file with the original name. [ex. ex. ClownJumps.mov]
5. I open Davinci Resolve and then the file updates automatically on my timeline.
Resolve needs to be closed BEFORE your rename the new file.
It takes me about 15 seconds to do this and it seems to work almost every time.
Hope this helps somebody
-Tommy