Looks like the five new fonts were widely available as early as 2021 April 28 - https://www.microsoft.com/en-us/microsoft-365/blog/2021/04/28/beyond-calibri-fin

Looks like the five new fonts were widely available as early as 2021 April 28 - https://www.microsoft.com/en-us/microsoft-365/blog/2021/04/28/beyond-calibri-finding-microsofts-next-default-font/ https://www.microsoft.com/en-us/microsoft-365/blog/2021/04/2... though Aptos isn't officially available as Aptos until 2023 July.