Hello,
I'm currently building ExpBuilder dev edition app, which uses Scene Viewer for displaying old georeferenced maps on a globe. Main source of maps is the David Rumsey collection, which also provides IIIF manifest link. This way I can save both time and space, and instead of downloading maps, georeferencing them in Pro and publishing to my account, I can just load the IIIF map in AllMaps.org and then use the XYZ map tiles link.
The problem is, I haven't found a way how to upload maps through this link to the Scene Viewer. In Map Viewer it works without any issue. In Scene Viewer, if I try to add it, this error message displays:

I did also try to first upload the map in the Contents tab, but it seems this type of URL is not supported (there is only option to "add to map", which does nothing).
One of the XYZ layers I tried to import: https://allmaps.xyz/images/6fd23a3dcd2f47c5/{z}/{x}/{y}@2x.png
Is this simply not supported or am I just doing something wrong?
Thank you for any reactions in advance.