Add the --all-fields flag to the list subcommand to also see the directory name where the SDK files for the given version entry are located.
For example:
> nrfutil sdk-manager list --all-fields
Version SDK Toolchain Directory
v2.9.0 Not installed Installed
v2.8.0 Installed Installed v2.8.0
v2.7.0 Not installed Installed
v2.6.2 Not installed Installed
v2.6.0 Not installed Installed
v2.5.0 Installed Installed v2.5.0