See the following from https://support.microsoft.com/en-us/office/upgrade-macos-to-continue-receiving-microsoft-365-and-office-for-mac-updates-16b8414f-08ec-4b24-8c91-10a918f649f8
To provide you with the best experience, Microsoft 365 for Mac, Office 2021 for Mac, and Office 2019 for Mac supports the three most recent major versions of Apple's macOS.
As of September 27, 2023, the three most recent major versions are macOS Sonoma, macOS Ventura, and macOS Monterey.
Note: As new major versions of macOS are made generally available, Microsoft will remove support for the oldest major version and support the newest and previous two major versions of macOS. Product functionality and feature availability may vary on older systems. For the best experience, use the latest major version of macOS along with the latest operating system updates.
You could either subscribe to Microsoft 365 or make a one-time purchase of Office Home & Student 2021.
Home & Student 2021 is compatible with Monterey. See the following from the above Microsoft support article:
Note that new installs of Office 2021 for Mac also requires macOS Monterey or later.