Hi, here is a best practices articles on this process: https://learn.microsoft.com/en-us/azure/azure-monitor/autoscale/autoscale-best-practices#choose-the-thresholds-carefully-for-all-metric-types
There is also a preview feature for predictive autoscaling for Virtual Machine Scale Sets (not App Service) which might be of interest as an alternative option for you: https://learn.microsoft.com/en-us/azure/azure-monitor/autoscale/autoscale-predictive