[4] At 15 years old, Grünberg was selected to compete at the 2016 Junior European Championships,[5] and the Dutch team finished 21st.

[9] He then competed at the 2022 World Championships in Liverpool where the Dutch team finished 13th in the qualification round.

[4] He was initially the first reserve for the parallel bars final at the Osijek World Challenge Cup, but he was able to compete after a withdrawal and placed seventh.

[14] He then competed at the 2024 European Championships where the Dutch team finished 12th in the qualification round, and he did not advance into any event finals.

[15] He won the all-around bronze medal and the horizontal bar title at the 2024 Dutch Championships.