Help with Hreflang tags

We run a multilingual website and publish a fair amount of content in English, French and German. I recently asked our Dev Team to improve/fix our Hreflang tags because a large percentage of our pages were missing self-referencing hreflang annotations. We also included the 'x-default' tags too (which I get isn't mandatory).

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I think Dev scripted something together to implement these changes across the whole site, and it looks like our recent articles (on the English site) include a self-referencing hreflang annotation and an 'x-default' tag by default in the HTML.

Here's what I mean:

 <link rel="canonical" href="https://www.example.com"/> <link rel="alternate" hreflang="en-US" href="https://www.example.com"/> <link rel="alternate" href="https://www.example.com" hreflang="x-default"/> 

^^ whilst this is only available in English at the moment; I suspect the hreflang tags probably won't do much, so is it still okay to have them there anyway? Will we get penalised by Google if the CMS automatically applies these tags if we only publish a piece of content under one language?