Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
I posted this earlier—and I'm working in a Mac, so things may be different in your PC, but basically you have three options: you can (1) purchase and download Office 2021 and unsubscribe from Office 365, (2) you can disable Copilot within Office 365, or (3) revert your Office 365 subscription to "classic" no-AI-enabled version.
To disable Copilot on a PC while retaining the current Office 365 subscription, you're going to go into Settings, click Personalization, go into Taskbar, and you will find a switch to toggle Copilot off there. Just be aware that with this method, you're going to be paying $30 more for the option of using Copilot, which will remain active im your subscription.
To obtain the "classic" version, you're going to log into your Microsoft account, navigate to the Subscriptions menu, and tell Microsoft you wish to cancel your Office 365 subscription. This will trigger Microsoft to give you options for AI-enabled (Copilot) OR AI-disabled ("classic") Office 365. Select the latter and your "classic" subscription sans Copilot will be initiated. Note that the Copilot icon will still appear in the top menu when you open Word etc., but it will be grayed out.