KDE Connect allows you to send individual files both ways and also to browse files on your phone from your computer. It is also capable of sharing the clipboard and open link from one device to another, as well as controlling input (mouse and keyboard) from another device.
Yeah I know but we were talking about CLI alternatives and the person said they used a quick python http webserver, but that doesn't work the other way.
Personally, I use pairdrop for that. Though, if I'm limited to CLI, woof has an upload option (-U) allowing me to select a file from the phone. Don't know of an easy way to do that from the builtin http.server.