You would need to install Windbg Preview from Windows Store

Get it from Get WinDbg Preview – Microsoft Store . If you use the ordinary Windbg that comes wint Windows SDK, this is what you get from trying to open it

WinDbg:10.0.19041.685 AMD64

Could not find the C:\Users\vimvq\Downloads\core_20211102_090430.dmp Dump File, Win32 error 0n87

The parameter is incorrect.

You also need to install .NET 5 version of sos.

dotnet tool install --global dotnet-sos

and once you used Windbg Preview to open the memory dump, run this command to load it:

.load C:\Users\<your user name>\.dotnet\sos\sos.dll

And now you can start debugging as usual