The potential £360m savings are allowed to be spread over 10 years, creating an annual net gain of £36m a year.
However, this is heavily offset by the need to start repaying debts now estimated to start costing £40m a year.
When added to the new interest payments of £7m a year, it leaves the council having to find £11m a year in cuts or savings.
Earlier this year it said there would need to be £8.6m in savings by 2028/29.
Council leader Joanne Sexton said the administration was “taking decisive action”.
“These are tough but necessary steps to protect local services and secure the borough’s long-term future,” she said.
The plans will go before full council on Monday.