It isn’t possible to do an in-place upgrade using windows server evaluation media. Licensed media must be used.
ExchangeServer2016-x64-cu12.iso link below:
https://www.microsoft.com/en-us/download/details.aspx?id=57827
ExchangeServer2019-x64-CU12.ISO link below:
https://www.microsoft.com/en-us/download/details.aspx?id=104131