The Autoselect Plugin will automatically select newly uploaded files for printing if there is an active connection to a printer and currently no print job running. By default it waits five seconds before selecting the file, giving printer power and connection plugins time to react to the upload. The delay can be changed in the plugin's settings.
Install via the bundled Plugin Manager or manually using this URL:
https://github.com/OctoPrint/OctoPrint-Autoselect/archive/refs/heads/master.zip