Afaik only 365 and 2021 will be ARM native and 2019 won't be.
Also be aware that unlike the Windows Office, Mac Office is supported only for 5 years and for the 2019 release, 2 years are already gone (it will be supported till Oct 2023, Mac Office 2016 is already unsupported since last October).
Also be aware that unlike the Windows Office, Mac Office is supported only for 5 years and for the 2019 release, 2 years are already gone (it will be supported till Oct 2023, Mac Office 2016 is already unsupported since last October).