He extended his contract with St. Pauli on 2 March 2018, signing an extension until 2019.[5]
Koglin left the club when his contract expired in June 2019, having made 83 appearances and scored nine goals in six years for the reserves in the Regionalliga, and made seven total appearances for the first team in the 2. Bundesliga and DFB-Pokal.[6]
1. FC Magdeburg
On 5 June 2019, Koglin signed a two-year contract with 1. FC Magdeburg, who had been recently relegated to the 3. Liga.[7][8][9] Under manager Stefan Krämer, Koglin made his Magdeburg debut on 28 July 2019 in an away game against FSV Zwickau. By the end of the season, he had made 28 appearances in the third division and managed to stay up finishing 14th.[10][6]
The following season, Magdeburg slightly improved and finished in 11th place, as Koglin made 21 total appearances. He left the club after the season, having made 48 total appearances for Magdeburg.[6]
VVV-Venlo
On 27 June 2021, Koglin signed a two-year contract with Dutch club VVV-Venlo,[11] who had recently been relegated to the second-tier Eerste Divisie.[12] The move reunited him with his former manager at St. Pauli, Jos Luhukay.[13] He made his debut for the club in VVV's season opener on 8 August 2021, also scoring his first goal for the club in a 2–2 home draw against NAC Breda.[14]
Koglin left VVV at the end of the 2022–23 season, as his contract was not extended.[15]
Roda JC
On 12 July 2023, Koglin signed a two-year contract with Eerste Divisie club Roda JC.[16][17] He made his competitive debut for the club on the first matchday of the season, starting in a 4–1 home win over Helmond Sport on 11 August.[18] On 14 October, he scored his first goal for De Koempels in the derby against his former club VVV, securing a 1–1 draw.[19]