Are there acts of worship in Islam that are conditioned upon abandoning specific sins before performing them?

Repentance to Allah is obligatory for all sins. If a servant repents from some sins but not others, their repentance for the sin from which they repented is valid, and they remain obligated to repent from the other sins.

Therefore, the validity of a girl's repentance from neglecting the hijab does not depend on her repenting from other sins. In fact, her wearing the hijab may motivate her to repent from other wrongdoings.

It is necessary to make repentance easy for people and to beware of making it difficult for them, as Allah Almighty says: "And indeed, I am the All-Forgiving to him who repents and believes and does righteousness, and then continues to follow the right guidance."