You can use Performance Metrics for your SF Nodes to get the Network and Disk information. You can also use Metrics Explorer to visualize the data from the underling VMs for your service fabric cluster.
As for application performance monitoring I'd add the Log Analytics agent as a VMSS extension to your cluster and then connect that to a Log Analytics workspace. There's a great doc showing how to do it with the Azure CLI. Once that's done you can monitor your application specific performance and scale down if your not utilizing your resources or up if your utilization is too high.