The Welsh Local Government Association warns that without long-term investment, essential social care would become harder to sustain.
The On Your Bike scheme combines practical skills with emotional support for young people.
Pay changes have left managers on the same pay bands as those they manage, a union has said.
The children's services have been rated as outstanding overall by Ofsted.
Haringey Council received a safeguarding complaint after 1,100 social work emails were left unread.
The city council is working with the charity Frontline to give graduates intensive practical and academic training over the next three years.
The report's findings have been described as "absolutely shocking" and "utterly negligent".
More children in care are now living in "family-style" residential homes, after a council was able to improve its process of matching young people.
An annual report highlights that staff turnover remains below the national average.
