He helped Breitengüßbach capture the 2016 NBBL title,[2] while averaging 6.4 points, as well as 1.5 rebounds a contest for Baunach in ProA play.

On 1 May 2017, Kulboka made his debut for Brose Bamberg in Germany's top-tier level Basketball Bundesliga, in a 61–74 win over Science City Jena, in which he recorded 13 points and 5 rebounds.

[22][23] During his debut game he scored 12 points per 13 minutes and helped his team to achieve an 88–87 victory over the Oklahoma City Thunder.

[25] He played his best game versus the China men's national basketball team, scoring 18 points and grabbing 4 rebounds.

[30] On 25 January 2023, Kulboka recorded a career-high 30 points (10/13 FG), four rebounds, three assists and 36-point PIR in a 81–72 home win over Budućnost VOLI.

In 27 domestic league matches, Kulboka averaged 12.1 points (shooting with 44% from the 3-point line) and 5.3 rebounds, playing around 28 minutes per contest.

[34] He scored a team-high 15.7 points a game in the 2016 FIBA Europe Under-18 Championship, en route to a silver medal.

[36] On 26 February 2018, Kulboka debuted as a member of the senior Lithuanian national team, by scoring nine points, grabbing five rebounds and dishing out two assists, and helped to crush Kosovo's national team, by a score of 106–50, during the 2019 FIBA Basketball World Cup qualification.