macOS counterpart of Windows startup batch file
The macOS counterpart is an AppleScript. You can create an AppleScript using Automator app and configure it to run upon system startup by going to System Preferences → Current User → Login Items.

To create the AppleScript, launch Automator.app. Under Library (in the left pane), select Utilities. From the centre pane, drag and drop Run Apple Script action into the pane shown towards right. Now enter the following script into the editor:

tell application "Safari"
    tell window 1
        set current tab to (make new tab with properties {URL:"https://www.youtube.com/watch?v=Kob0G2hE8IY"})
    end tell
end tell


This is how the final result will look like:



Now save the workflow by selecting File → Save... command. When saving change the File Format to Application.

Now go to System Preferences → Users &amp; Groups, select your user under Current User and click on the Login Items tab. Click on the + button shown at the bottom and select the app saved in the last step. This will add the workflow that we created to the list of items set to be opened automatically when you log in.