A member of AV Suomi club in Velsen training under Laurent Meuwly, Dobber competed at his first senior national event at the 2017 Dutch Athletics Championships and placed fourth in the 400 m. His first national podium finish came at the 2018 Dutch Athletics Championships, where he was runner-up to Tony van Diepen. He improved his personal best time to 46.45 seconds that year. Dobber managed third in the 400 m at the 2019 Dutch Indoor Athletics Championships, which brought him a place on the Dutch team for the 2019 IAAF World Relays. In his senior international debut he placed fifth in the B-final with the Netherlands 4 × 400 metres relay quartet, alongside Terrence Agard, Liemarvin Bonevacia, and van Diepen. He also placed second at the 2019 European Team Championships First League with the Dutch relay team.