This guide is relatively straightforward and simple. It takes a minute or two and skips all the download steps (aside from the filecheck, just to be safe). After following these steps (and linking PSO2 to your epic games account above), you will be ready to play PSO2 NA Epic Games Store version! \o/
Please note that, after doing this, you will be able to swap between the Microsoft Store,Steam, and Epic versions of PSO2NA at any time, with them all working as expected. (Assuming you have them installed and set up)
In order to circumvent the Epic Games Launcher entirely, the Tweaker will use the open-source Legendary client. On first launch, the Tweaker will download it and walk you through the very short setup procedure. (This will only happen once)
Now that you can use the Epic Games version, switch the version back to the first version of PSO2NA you played. Launch the game through there like before to get your code (Select a ship -> Support Menu -> Issue Account Link Code). Then close the game, switch to the Epic Games version. Launch the game, put in the code, and enjoy the game! \o/
In order to use a different Epic Games account, you will need to delete your existing data from Legendary. Go to where your Tweaker is, and open a command prompt window. You can do this by going to the folder where the Tweaker is, then typing "cmd" at the top bar and hitting enter, like so:
Once you have this prompt open, type
legendary.exe auth --delete and hit enter. Now when you try to launch through the Tweaker, it will have you re-do the account linking.
The Tweaker -will- try to import existing Epic Games Launcher account info though, so make sure you sign into the Epic Games Launcher with the new account before you launch via Tweaker if you have Epic Games Launcher installed. If you don't, then don't worry about it.