Why after updating .NET core extension in vscode do all my builds want to use .NET 8 and how do I rollback?

I opened VS Code and it came up with notification on .NET Core extension (at least I'm pretty sure it was that, though it seems to have disappeared - see point 2 below) saying I needed to update. Without properly thinking about it I selected to update and it appeared to do so ok - at least I did not see any errors.

However once that was complete:

I can no longer build any of my projects from vscode (they still build from the command line) - It comes up with an error:

Debugging C# files without a project is only supported for .NET 10+.

Build output looks like:

C:\Users\lc922756\practicecoding\csharpprac\testingiterators\testingiterators.csproj loaded by C# Dev Kit 2025-11-25 11:04:56.745 [error] [textDocument/_vs_getProjectContexts] [BuildHost PID 18612] The BuildHost process exited with -2147450730. Process output: You must install or update .NET to run this application. App: c:\Users\lc922756\.vscode\extensions\ms-dotnettools.csharp-2.102.30-win32-x64\.roslyn\BuildHost-netcore\Microsoft.CodeAnalysis.Workspaces.MSBuild.BuildHost.dll Architecture: x64 Framework: 'Microsoft.NETCore.App', version '8.0.0' (x64) .NET location: C:\Program Files\dotnet\ The following frameworks were found: 6.0.16 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] 6.0.36 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] 7.0.5 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] 7.0.20 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]

So it apears to be insisting on using .NET 8 (not currently installed)

I thought I could go back to the extension and rewind it, but the list of installed extensions no longer includes it.

Questions

Does anyone have any idea why it is suddenly insisting on .NET 8 for builds (regardless of the framework setting on the app)?

Does anyone have any idea why I can no longer see .NET Core extension in installed list? Has it been replaced by something else in the update?

Does anyone know how I can wind back the update I did to what I had previously, so I can again build with .NET 7?

I guess one of the solutions is to install .NET 8, which for the things I do on VS Code would probably not be too much of a problem, but I also work on large projects which must use .NET 7.

I'm thinking if I do install .NET 8, it could well mess with global settings that would make it a pain to force use of .NET 7 elsewhere (Visual Studio, command line). Is that that the case?