[3] He achieved a race victory at the Lausitzring, and with nine further podiums Seppänen finished third in the standings, only behind Red Bull juniors Jak Crawford and Jonny Edgar.

[4][5] Seppänen made his debut in the Formula Renault Eurocup as a guest driver for R-ace GP in the final round of the series' history at Paul Ricard.

In 2021 Seppänen progressed to the Formula Regional European Championship, partnering Nico Göhler and fellow Finn Patrik Pasma at KIC Motorsport.

[10] In a series that had been significantly weakened following the introduction of a rule which mandated each lineup to contain at least one silver-ranked driver, Seppänen and Owega took four victories, including a weekend sweep at the Sachsenring, to win the title in the final round.

[11][12][13][14] In 2024, the Finnish driver returned to defend his GT Masters crown, this time being joined by Tom Kalender at Landgraf.