Hreflang tag implementation - multiple cities in same country

Hi guys, I wanted to ask if any of you can help me with a doubt I have regarding hreflang.

So I have a site in English in different countries. Till now it was easy to implement the tag as it was like this:

<link rel="alternate" href="https://madrid.example.com/" hreflang="en-ES" />
<link rel="alternate" href="https://berlin.example.com/" hreflang="en-DE" />
<link rel="alternate" href="https://paris.example.com/" hreflang="en-FR" />
<link rel="alternate" href="https://example.com/" hreflang="x-default" />

But now, we also have a subdomain in Munich. So should i add this in the hreflang code?
<link rel="alternate" href="https://munich.example.com/" hreflang="en-DE" />

I'm asking this because the language and country code is the same for berlin and munich and I don't know if it'll be correct to put both with the same hreflang. I wish it worked on city-level as well.

Thank you in advance for your help.