Welcome to Microsoft Q&A platform and thanks for posting your query here.
I understand that you want to know if the SharePoint App registration has to be multitenant to use Azure Data Factory SharePoint List Connector in case ADF and M365 are in different tenants.
- Currently I do not have an environment to repro your scenario, however , from my research I found that if you want to access a SharePoint site from resource in another tenant, you probably need Multi-tenant application.
- Single-tenant apps are only available in the tenant they were registered in, also known as their home tenant. Multi-tenant apps are available to users in both their home tenant and other tenants.
Below are the resources you may find helpful for the above query:
- Copy data from SharePoint Online List by using Azure Data Factory or Azure Synapse Analytics
- Building Multi-tenant applications for SharePoint Online
- How to access a SharePoint site in another tenant
Hope it helps. Please let us know how it goes. Thankyou