The Death Eaters were hesitant in lending their full support to Voldemort during his initial rise to power because they were unsure of his ultimate goals and methods. Voldemort's ideology and plans for pure-blood supremacy were not shared by all Death Eaters, and many of them had their own agendas and personal motivations. Additionally, Voldemort's secretive nature and tendency to act independently made some Death Eaters wary of fully aligning themselves with him. Furthermore, after losing the first war, many Death Eaters were captured or went into hiding and didn't want to risk their lives or freedom again.
It's worth noting that not all Death Eaters were hesitant and some of them were true believers in his cause. The support for Voldemort was not unanimous and it varied among the members of the organization.
The Death Eaters were reluctant to lend Voldemort their wish because they were unsure if he could bring them the power and control they sought. Voldemort had been weakened by his previous battles with Harry Potter and had been in hiding for some time, and the Death Eaters weren't sure if he was strong enough to lead them anymore. Additionally, the Death Eaters were wary of the power shift that would come with Voldemort's return and worried about how it would affect their positions within the organization.