What libraries are you referring to, because outside of niche things like WCF there's very little left that doesn't run on every OS .NET 6 runs on now. Of course COM won't run on Linux.
Niche stuff like enterprise in-house build built 2002 and 2015 when Windows was the only game in town (mono wasn't really taken seriously), enterprise CMS like Sitecore and SharePoint, GUI frameworks (component libraries from DevExpress, ComponentOne, Telerik among others).
And all the stuff Visual Studio Professional/Ultimate have on the box and Rider will never support, nor VSMac/VSCode.