Start and End IPs are too open, they may lead to cross account access for Azure Synapse Firewall Rule.
In Azure Console -
In Terraform -
References:
https://learn.microsoft.com/en-us/azure/synapse-analytics/security/how-to-create-managed-private-endpoints
https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/synapse_workspace
https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/synapse_firewall_rule