On December 2, 2017, Twardosz was appointed to the World Cup team. Together with Adam Cieślar , Szczepan Kupczak and Paweł Słowiok , he took tenth place in the relay, whereas he was not used in the individual. At the Nordic Junior World Ski Championships in Kandersteg in 2018 , he finished 21st in the Gundersen singles, 22nd in the sprint and twelfth place with the team. After becoming Polish champion for the first time in Zakopane in February 2018 , he made his debut at the end of the season in Klingenthal in an individual competition in the World Cup.
After he was able to collect Continental Cup points again in January 2019 , he started again in the World Cup. Although he still failed to reach the points, he was still nominated for the Polish squad for the Nordic World Ski Championships 2019 in Seefeld . There he finished only in the lower ranks in the individual competitions. Together with Adam Cieślar, Szczepan Kupczak and Paweł Słowiok, he finished eighth in the season. In February he also took part in the Cross-Country Slavic Cup in Zakopane, where he won points directly in sixteenth.
After the 2019/20 season, Twardosz ended his career.