Each pixel of such a scanner would need to somehow scan the spectral content. For example, imagine an array of fibers each transporting light from image plane pixel coupled to a spectrometer (bulky, expensive). Slit (a.k.a. push broom) scanners take each pixel of its slit and disperses the light perpendicular to the slit onto a 2D sensor array (more compact, 1D mechanical scan required). I recall seeing spectral (color) filters made from dispersive materials sandwiched between rotating polarizers to filter (scan) the light entering camera (expensive, compact).
Having paid for and enjoyed Narwhal and Apollo, I really hated the official app. After some digging, I found https://github.com/lo-cafe/winston and that's working for me. It's not simple - you have to generate your own Reddit app id and secret, be able to Xcode from source and have a valid Apple ID to install the IPA, but it's worth it to me to spite the enshittified app.
xattr -c `which whosthere`
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