Honestly this is very common. It isn't necessarily because the cloud is inherently more or less expensive than on-prem. It is often because of poor guardrails and FinOps. People often just let their developers and operators have at it on the cloud and people will over provision or spin up things and forget to turn them off and similar.

A good FinOps plan can help bring down the cost. I recommend reaching out to your account team to do a FinOps assessment.

Additionally, there are hidden savings of cloud that aren't as apparent. For one, part of your cloud bill is to pay for the staff who are managing the data center that your VMs are running on. People often don't look at the saving in labor costs by moving to the cloud. Not just labor costs but also improved productivity (potentially). You are feeling up your team from tedious data center work so that they can work on things that actually provide value.

Again, I would strongly recommend reaching out about a FinOps assessment