Can one embed a 3D viewer in a keynote or powerpoint presentation

Other solution, the 3d warehouse.

publish your project there, and access it through your browser (no the in-app warehouse)

it allows you to download in USDZ, even if you upload it as a private model.
(private models don’t have AR mode, but do have the 4 format choice)

Capture d’écran 2024-03-02 à 16.47.32