Here are the features that are currently not available in the Cloud:
Export to PDF or Word: You can export the Confluence page to Word/PDF, but the styling won't be exported. For example, consider Table Plus macro, when you export the Confluence Page to PDF, the table will be exported but the styles/colors won't be exported. Note: Exporting the CSV/JSON tab to Word or PDF is not possible.
Jira Issue/Filter macro in Advanced Tables macros: This macro is not currently available in the cloud, but we are working on something that will enable it.
Page Properties Report macro in Advanced Tables macros: In the Cloud version, "nested tables" are not possible, but Atlassian recently released a feature for Confluence called "Table Extensibility." This feature is the closest to the "Nested tables" server functionality. We intend to work on including this functionality in the future.
Using customized CSS for tables in macros: It is currently possible to include elements in rows and columns based on CSS. The process is tedious, but it is feasible.
Preview in the macro editor: We have four macros in the cloud, none of which have a preview like in the Server. We plan to work on this in the future.
As per the documentation, the details of the other features have been updated, but Confluence Cloud doesn't support them. You can refer to Migration from server/DC to Cloud.