General Syrskyi is less well-known among the Ukrainian public compared to Zaluzhnyi and Budanov. Ironically so in some respects, as Syrskyi was reportedly the commander of the defense of Kyiv, the strategist behind the successful Kharkiv counteroffensive in the fall of 2022, and the defense of Bakhmut.
He's no doubt extremely experienced, but he has large boots to fill. Zaluzhnyi was extremely popular among both the Ukrainian public and military. And right now there is much uncertainty about the state of the war given a lack of clarity regarding American aid to Ukraine.
Charts from a KIIS survey from December.