I found the easiest way to send files between my Android phone and desktop - and it's free

Localsend offers a seamless solution for transferring files between Android and desktop systems. This free app automatically discovers other devices on the same network, allowing users to easily send files, text, or clipboard content between Android phones and Windows, MacOS, or Linux computers without manual configuration. Installation is straightforward across all platforms, and the simple send/accept interface makes file transfers effortless.