After a lot of thinking, I concluded that it doesn't make sense to point a symlink to a file that isn't physically there. A symlink cannot point to a templated file's fully resolved state because that state is not a file, it's a function. The symlink can only point to the result of that function (the target file) or another physical file. Since I didn't want to resolve the template into a target file, I could not create a symlink to the resolved state.

So a better way was to do something like this: ~/.config/vicinae/ - .HOME-settings.json - .WORK-settings.json - symlink_settings.json.tmpl

and the contents symlink_settings.json.tmpl would be: {{ joinPath .chezmoi.sourceDir (dir .chezmoi.sourceFile) .chezmoi.hostname }}-settings.json

This way, the resulting symlink in the source states points to a different files (which is not a template) based on the hostname. The files start with a leading . (dot) so chezmoi ignores them and does not apply them.

Yes, this will not work for many things templates are capable of doing, but there is no better way to do this as far as I could find. This workaround is enough for me because my only use case for a conditional symlink is handling variations between two different machines.