If you are receiving a K-1 for services performed for the partnership, then you are a partner for the purposes of the income reported on the K-1, not a sole proprietor (although you would be considered to be self-employed).
If there is some other sort of arrangement between you and the partnership (i.e., you are not a partner, but are an independent contractor who performs services for the partnership), then you should not be receiving a K-1 as a tax reporting statement (most likely it would be a 1099-NEC). If that is the case, then you need to speak with the party responsible for preparing the tax reporting statements for the partnership.
