She won in the 4x400 metres relays a silver medal at the 2018 World Indoor Championships and a gold at the 2018 European Championships, running in the heats. In the same event, Kaczmarek earned a bronze medal at the 2021 European Indoor Championships. In May, she secured a gold in the 400 metres at the European Team Championships, whose Super League events took place in Chorzów, Poland; she won her second gold medal with Polish 4x400 m relay team.