Hi @F_Quint
I was able to get it working.
For spaces in the URI %20 does work
But for spaces in the Body for the Metadata type than you must use _x0020_ for the spaces.
Now if you want to get this value dynamically, you can use 2 http calls like below:

Than I am using a parse JSON:
I put {} as the schema so I can run the flow and get sample data to generate from sample
than my second http call looks like this:

I am grabbing type from the parse json
My Successful run:
