Will I loose the intellectual property rights to my content when cooperating with a brand on linkr?

Not at all, all your content and channels will still belong to you! For certain campaigns or cooperations, brands will ask for allowance to use your content for e.g. reposting it on their own channels or using it on their homepage or for advertising. By applying to such a cooperation, you are giving your ok to the brand to use the content you have generated. However, the content itself will always be yours.