Plus now we have Jetbrains Rider. So there's an excellent non-Microsoft IDE alternative.
Rider is no joke. If you haven't used it or gave up on it a few years back, give it a shot. There are a few things it can't do like attach to managed modules hosted in unmanaged processes but it's a joy to code in.
Granted, the .NET Foundation is not the Apache, Eclipse, Linux or CNCF Foundation and it is dominantly financed by Microsoft, but there are relative important peers like AWS or RedHat involved.