I can confirm, it still doesn't work in 2024. I'm going the Classic Map Viewer route. It is hard to understate the importance of relates; every Big Customer uses them for inspections. For many Big Customers, data will remain on SDE in SQL Server. SDE/SQL can do a lot that AGOL/Portal can't, by design. (SQL views, granular security management) There are various reasons to keep things out of Portal federation. Server/Enterprise/ProductName and SDE are where Big Customers store Important Data. 'Classic stack' stand-alone server, classic map viewer, WebApp Builder, ArcMap often provide mission-critical capability like relates that new Map Viewer, Portal, ExpB, Pro lack. I know they'll get there but I'll inquire on this at Dev Conf with product teams. edit: I added to classic map viewer and my inspection app was up and running in WebApp Builder and Field Maps in under a minute for real. I understand MVC in ExpB and 3D/VR/ probably AI soon in the JSAPI 4 but the old stuff provides capability; just works, and the interface is efficient and intuitive. TL;DR: use classic map viewer for now.