[4][5] His season would start out slowly compared to his teammates Kas Haverkort and Mari Boya,[6] with just one podium and pole position scored in race three in Navarra to show for his efforts.

[8] The Swiss driver scored three more podiums in the latter half of the campaign, finishing the season in fourth position in the standings, tied on points with fellow rookie Thomas ten Brinke.

[9] In 2021 Dufek moved to Van Amersfoort Racing, partnering Oliver Bearman and Nikita Bedrin in the Italian and ADAC Formula 4 series.

[11] He scored another podium in Imola, and went on to make a bold call to switch to rain tyres during the final race at the Red Bull Ring, which allowed him to charge to second place.

[20] Having taken part in post-season testing with MP Motorsport and Van Amersfoort Racing at the end of 2021, Dufek signed for the latter team to compete in the Formula Regional European Championship, driving alongside Levente Révész and Kas Haverkort.

[21][22] Before the season, the Swiss driver competed in the first three rounds of the Formula Regional Asian series for Hitech Grand Prix, amassing two rookie podiums, ending 18th in the standings.

However, a sudden upturn in form at the Hungaroring round with strong points finishes, followed by a double podium at the Red Bull Ring after the summer break, propelled the Swiss driver into the top 10 in the standings and rookie title contention.

[33][34] Despite a maiden pole position at the Hungaroring,[35][36] Dufek experienced a drop in speed due to what he described as a "recalcitrant engine", and opted to pull out of his contract during the summer break.

[38] After leaving Formula Regional midway through 2023, Dufek joined the Euroformula Open with CryptoTower Racing Team starting from the fifth round at the Red Bull Ring.