Can I release an app without the device?

Yes you can build for archive without having a device connected.

Step 1: Set the active scheme to 'iOS Device'

Step 2: Product > Archive

Step 3: Organizer > Archives

Note: The screenshots were taken without a connected device.

As at now, on Xcode Version 11.3.1 (11C504), There is nothing like "IOS Device" incase you're looking for that and could not find it.

It's now "Generic IOS Device"

I'm note sure but their is something about this method, it generated a very ridiculous size of Archive for me, I'm talking about 600MB kind of file, might just be because I'm building from a cross-platform perspective.

Enjoy.