A family of Microsoft word processing software products for creating web, email, and print documents.
Thanks for the screen shot. It says that your installation isn't activated. In your Microsoft account, which product name is indicated there? Maybe your computer is trying to activate the wrong version.
On the Word menu, click Sign Out. Restart your computer and then restart Word. Does that let you choose the correct sign-in?
If not, you may have to remove the license files from your Mac and start over. See https://support.microsoft.com/en-us/microsoft-365-activation-licensing/how-to-remove-office-license-files-on-a-mac .