How do you manage remote dev workstations in the cloud?

We try to balance cloud spend vs developer efficiency in our team. From time to time devs needs stronger instances (CPU/GPU/RAM/extra machine, etc) with their dev environment ready. However, the transitioning is cumbersome, although we added some scripts and automation. Machines tend to be idle a big portion of the time. Are there good solution to reduce devops burden from the devs while reducing wasted resources?