Throughout her career Knapik has taken on a wide operatic repertory, singing lyric and spinto roles across the 19th and early 20th-century canon. Press and season archives cite her in leading parts such as Tosca and the title role in Rusalka, and in concert/semistaged assignments including Mozart and Verdi. Reviews of productions in which she appeared emphasize both vocal heft and dramatic intelligence, noting that her performances often become focal points of the productions. Her work with companies such as Sarasota Opera and other regional houses in North America brought her to audiences beyond the Polish and Canadian communities where she was best known.

Alongside staged opera, Knapik has maintained a substantial concert career. She has sung as a soloist with orchestras and choirs in large-scale works — for example, performances of Mozart’s Requiem and other staples of the sacred/oratorio repertory. She has appeared in prestigious small halls and large venues: a Carnegie Hall recital appearance (Weill Recital Hall, presenting Chopin songs with pianist Michel Brousseau) is among the highlights recorded in press announcements and artist biographies. Her concert work also often foregrounds Polish song and composers, positioning her as a cultural bridge between Poland and North America.