I need to check, but I think the nano converter plate may have a problem in V7.0.0-Alpha2.
This is 7.0.0-Alpha1 (in /models from https://build.openflexure.org/openflexure-microscope/openflexure-microscope-v7.0.0-alpha1.zip)
This is 7.0.0-Alpha2 ( https://build.openflexure.org/openflexure-microscope/v7.0.0-alpha2/models/nano_converter_plate.html)
I don’t think that the hole for the USB has moved in the Pi tray from Alpha1 to Alpha2.