[1] Jan Guńka gained his first international experience at the 2019 Youth World Championships, achieving a best individual result of 22nd place in the sprint.

The Junior World Championships of the same year were highly successful for him, winning the bronze medal in the sprint behind Denis Irodow and Fabio Piller Cottrer.

Despite his successes in the junior category, it was somewhat surprising after the season's end that he clinched the Polish national title in the individual event, surpassing competitors like Grzegorz Guzik.

At Pokljuka, he was the leadoff skier for the mixed relay alongside Marcin Zawół, Kamila Żuk, and Joanna Jakieła, finishing in eighth place.

In Ruhpolding, Guńka, along with Marcin Zawół, Grzegorz Guzik, and Andrzej Nędza-Kubiniec, achieved Poland's best result in a men's relay since the 2006/07 season with a 10th-place finish.