Hello Zeyad Al Mothafar,
Welcome to the MS Q&A Forum.
Running a fastAPI Python code on a single T4 GPU VM in Azure to provide services that call external APIs and run Python code locally can potentially face performance and network issues. As example, If your services are calling external APIs, network latency can be a bottleneck.
This article describes virtual machine (VM) generic performance troubleshooting through monitoring and observing bottlenecks and provides possible remediation for issues that may occur. Besides monitoring, you can also use Perfinsights which can provide a report with best practices recommendations and key bottlenecks around IO/CPU/Memory. Perfinsights is available for both Windows and Linux VM's in Azure.
Hope above answers your question and concern. Let me know if you need additional assistance. If the answer was helpful, please accept it and complete the quality survey so that others can find a solution.
Olga Os.