Accessing PoE2 through the standalone client without primary login (email)

Hey there, As stated in our Early Access FAQ:

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Community_Team wrote:

If you have purchased a key and/or have access granted for one PC game client (Stand-alone, Steam, or Epic), but wish to play on another game client, you will be able to do so by claiming a key to unlock access to that client. These are available at my-account/early-access and can be redeemed on the relevant platform's store. Please note these keys only unlock the client in your library, they do not on their own provide early access to your account.

If your Path of Exile account is already linked to Steam, and your account has been made eligible to participate in Early Access either by purchasing a supporter pack or by receiving a key from another player, you should be able to have access across all PC platforms as quoted above. You may need to visit the page linked to acquire a Steam client key to add the game to your Steam Library. But you can still play via Standalone, Steam, or Epic once they are available to download.

Edit: To more directly answer your question, if you already play through Steam using your Path of Exile account, then yes, you can use the same Game login information to play on standalone.