Hello Alex,
Welcome to the Microsoft community, my name is Taiwo I'll be happy to help you today.
You could try to follow these steps to see if it works:
Open the Windows Run dialog (Windows Key + R).
Copy the following path to the Run dialog, and then press Enter. %AppData%\Microsoft\Windows\Start Menu\Programs\Startup
Open the Start Screen, right-click the Office program you want to automatically start, and click Open file location. This might be under the More submenu.
a. Tip: If MS Team program isn’t listed, right-click the Start screen, and click All Apps. Copy (Ctrl + C) the Team shortcut and then paste (CTRL +V) it to the Startup folder you opened in Step 2.
Teams will automatically start the next time you start your computer. If you ever want to remove a program from autostart, delete the shortcut from the Startup folder (Steps 1 and 2).
Best Regards, Taiwo