The disk unlocking is just because you have FileVault enabled. Usually the Filevault password is cryptographically linked to your login and you unlock the disk and your account when you start the computer.
The picture looks like you are in Recovery Mode? In that case the disk is not unlocked on boot and you have to do it manually. Can you actually run a normal boot or did you delete Windows by erasing/removing the Boot Camp partition from Disk Utility in Recovery Mode - and probably messed up your boot sequence if your computer was set to automatically boot to Windows?
Similarly, if you are in Recovery Mode, you wouldn't automatically have Internet (or at least WiFi) and would need to manually select and connect to your Wifi access point.
What exactly did you do - and what are you trying to do now? Your simplest solution may be to hold the Cmd key at startup, select macOS as your startup disk, and then fix your startup disk selection from System Preferences...that is, unless a heavy-handed attempt to remove Windows without doing it using Boot Camp Assistant snookered your disk partition table and the Boot Manager can't find a bootable disk...
