Since it's a VST3 plugin, there must be a .vst3 file for it in your VST3 folder, as that is the only place any DAW looks for VST3 plugins.
It doesn't necessarily need to have the same filename as its plugin name, plugins are recognized by their plugin ID.
Maybe try this: re-install Spectralayers, then open your VST3 folder and sort it by date. The newest file should be the Spectralayers VST3.