Hi @MTrummer you can try this instead this is how I do it
I have an Option set with values as below

Now Check my flow and see the magic
so what I did here is I created a json of the option set values and the corresponding label as as shown in the below flow

Step - 1 Create json as below with your values and labels

Step -2 Create a string variable and set its value to your option set value from dynamic contents.
Step - 3 Use the below expressions in the place where you want the label value to appear
Output -


Hope that helps !
Let me know incase any issues.
If this resolves your issue please mark this post as answered and hit me a thumps up.
Thanks and Regards,
Vidit