You question is not clear. .net core does not update in place. Each update is installed into its own folder. Some patch installers can be configured to delete lower version patches. But installing a newer version does not delete previous versions.
also .net core apps a built against a particular version. They will run with the lasted patch version installed, but not a new You can only update the patch version without building the app for a later version.
so this means if you delete the .net 5 runtime before upgrading all the .net 5 apps, they will not run.
see:
https://learn.microsoft.com/en-us/dotnet/core/additional-tools/uninstall-tool?tabs=macos