Teams tag is mainly focused on the general issue of Microsoft Teams troubleshooting. According to your description, your question is not in our support scope. So I will remove teams tag from your thread. Thanks for your understanding!
It's the EFI shell, not PowerShell, so I will remove PowerShell tag from this thread. \EFI\Microsoft\boot\bootmgfw.efi is the WIndows Boot Manger and it seems to be missing. You can try the Startup Repair.