In the 2018–19 ACB season, his last before moving to CSKA, he played 33 games, averaging 9.3 points (career high in Spain), 2.5 assists, and 5.6 rebounds.

[9] On 2 July 2019, CSKA Moscow announced that Voigtmann had signed a 2-year deal with the team with an option for a third year.

I just couldn't stay in Russia and carry on as if nothing had happened...."[15] The team accused him of violating his contract.

[13][16] On 2 September 2022, Voigtmann signed a two-year contract with Olimpia Milano of the Italian Lega Basket Serie A (LBA) and the EuroLeague.

In 2014, he made his debut in the senior German national team, when he played in the qualifying rounds for EuroBasket 2015.

He scored a jumper in a team-high 13 points for his national team against Russia, leading Germany to a 69–67 win.

[20][21][22] At Tokyo 2020, Germany men's national basketball team managed to reach the quarterfinals, something that had happened only in 1984 and 1992.

[24] He grabbed 13 rebounds in Germany's loss to eventual bronze medalist Australia, in their third and last game of the group stage.