Achievement: Multitasking
Solution:
In order to achieve the Multitasking achievement on EA SPORTS FIFA 23, you need to complete a minimum of 10 activities during a season on the Player Career Mode game mode.
It is worth noting that "activities" includes both decisions and shopping.
The quickest way to achieve this achievement is to use Messi from Paris SG (PSG). Starting at the main menu, select the "Play Modes" section, then select "New Career". After you have selected "New Career", you'll want to choose "Use Initial Squads" and from there you'll want to select "Play As Real Player". Navigate to Ligue 1, and choose Paris SG (PSG) as your team. You'll be presented with a list of players who play for Paris SG (PSG), you'll want to choose Messi and then press "Advance". You'll be shown a "Career Settings" screen, but as far as I am aware, you do not have to alter any of these settings. So continue on by pressing "Advance" and after the loading screen you can save your career if you want to (not necessary though). Now you'll find yourself on the Player Career Mode main menu (you should see Messi standing idle on the right of your screen) and you will have £1,000,000 ($1,000,000) in your wallet. From here, you can navigate to the "Activities" section on the Player Career Mode main menu screen. You will already have one decision you can make under the "Decisions" tab, click on "Greet Your Teammates" and choose any of the three options (doesn't matter what one). That's one of the ten decisions completed already. You should now navigate to the "Shopping" tab where you will have nine different things you can buy. You will want to buy all of the nine different things (you'll have more than enough money) and once you have bought the final thing you can currently buy (for me it was "Build A Swimming Pool At Home"), the achievement will pop.
If you want a much more simplified version of the above, read this:
Main Menu -> "Play Modes" -> "New Career" -> "Use Initial Squads" -> "Play As Real Player" -> Choose PSG -> Select Messi From The Player List" (Now You'll Be At The Player Career Mode Main Menu Screen.) "Activities" -> "Decisions" -> "Greet Your Teammates" (1/10) -> "Shopping" -> Buy All Nine Shopping Options (10/10).
This achievement popped immediately for me after following these exact steps.
Congratulations on the achievement!!
-Sodzs.