It's just .NET now, without the Core part. Mono remains a runtime flavour for special targets but it's being slowly phased out in favour of CLR even on those special targets (for example iOS which has historically relied on MonoAOT, but now can be targeted with NativeAOT too).

Also, I'd really love if people stopped exclusively attributing .NET's progress to Microsoft. Yes, MSFT does the steering and funding, and employs teams working on the ecosystem, but the development happens in the open, and a lot of runtime improvements have been community contributions.