OK.. me again..
What if in this order:
1) i set the Content Control first with a specific Font, size and Color, then
2) i set as default to "Keep Text Only" in the "Cut, copy, and paste" option for all types of Pasting options.

This will grant me that with a normal CTRL+V the text will be plain and adjunt to the Content Control i guess..

Now i guess i want to apply this "Default setting" ONLY to this document and not to ALL Words documents...