[3] Brünker is from Villingen-Schwenningen; in August 2018 he stated that a number of people from his village had bought Bradford City shirts and were watching matches online.

[10] He made his debut for the club on 27 January 2018, appearing as a substitute in a 4–0 league defeat at home to AFC Wimbledon.

[11] On 12 April 2018, after Bradford's poor form, manager Simon Grayson suggested Brünker was close to making his first start for the club.

[16] He left the club in January 2019, to return to Germany,[17] signing for SG Sonnenhof Großaspach on a contract until June 2020.

[22] On 12 March 2024, he scored the winning goal for the latter in the stoppage time of a 2–1 victory over Borussia Mönchengladbach in the DFB-Pokal quarter-finals.