Can I use Cozy to sync my KeePass password keychain?

No, Cozy is not compatible with KeePass.

A few years ago, when we decided to integrate a password manager into Cozy, we studied the different existing solutions, so KeePass. But the way KeePass allows you to synchronize your keychain between several devices did not seem ideal to us.
We preferred BitWarden, another free solution, which we integrated into Cozy. This is the Cozy Pass app.

You can import your passwords from KeePass into Cozy Pass , and use our application to access your passwords from your computer as well as from your phone. But it is not possible to use your Cozy to synchronize your KeePass keychain between your devices.