I think that might have been the case a while ago but they have even dropped .net-core and it's now just .net and cross platform.
It appears to have been the case since .net 5 (2020) (I've also stopped paying attention to MS a bit before then).
"Yes, .NET 5 is cross-platform and can be installed on Linux, Mac, and Windows. It aims to provide a consistent development experience across platforms by unifying different .NET flavors, including .NET Core, .NET Framework, .NET Standard, and Mono. .NET 5 also aligns all frameworks to support a common set of APIs, making it easier to build cross-platform libraries."
It appears to have been the case since .net 5 (2020) (I've also stopped paying attention to MS a bit before then).
"Yes, .NET 5 is cross-platform and can be installed on Linux, Mac, and Windows. It aims to provide a consistent development experience across platforms by unifying different .NET flavors, including .NET Core, .NET Framework, .NET Standard, and Mono. .NET 5 also aligns all frameworks to support a common set of APIs, making it easier to build cross-platform libraries."