As the game requires online features, Epic Online Services ("EOS Overlay") must be installed and activated, and "Offline Mode" must be disabled in order for the game to boot! (otherwise it gets stuck on Step 1)

Please note that this is not the default!
Epic online services must be installed manually;
Offline Mode is enabled in Heroic Launcher and Playnite's Legendary plugin by default

Instructions for Heroic Launcher:

Install "EOS Overlay":

• Settings -> Advanced, scroll down to "EOS Overlay"
• Click Install (You can ignore any errors, as long as "Check for updates" button turns green)

Make sure that the game is not in Offline mode:

• Right click the game -> Settings
• Make sure that "Run game offline" option is disabled

Instructions for Playnite (With Legendary Launcher plugin):

Install "EOS Overlay":

• Add-ons (F9)
• Extension settings -> Libraries -> Legendary (Epic)
• Advanced -> EOS Overlay -> Install

Disable offline mode:

• Right click the game -> "Legendary Launcher settings"
• Make sure that "Offline mode" is disabled

if everything is set up correctly, you should be able to bring up the Epic Games overlay menu by pressing Shift+F3, like on the screenshot below: