I tried removing the C:\Program Files\Steinberg\VSTPlugins\Native Instruments from the VST2 search path and restarting Dorico. No luck with that, unfortunately. Also, there is only a single VSTPlugins folder present.
As mentioned in an earlier post, the weird thing is that Cubase 10.5 actually also blacklists Kontakt 6 (Kontakt.dll), but here adding it to the whitelist solves the issue. This does nothing for Dorico, unfortunately.