Dotnet Core - Self-contained very low performance when call Soap Service over WCF

Question

My context:

• I deploy an Dotnet core web API on Self Contained style (Stand Alone:Kestrel)
• My Application just call other Soap Webservice (Generated skeleton over svcutil 2.0.2)
• When I load test with about 50 threads (concurrent request), I get a very high latency, requests blocked somewhere, I observe that it wait to open more and more Thread to receive request and open connection to Soap Webservice Endpoint
• This is not occur on IIS (using AspNetCoreModule)
• This is not occur when my application call database request I found some topic related to my issue but they cannot resolve it completly

https://learn.microsoft.com/en-us/archive/blogs/wenlong/why-are-wcf-responses-slow-and-setminthreads-does-not-work

https://learn.microsoft.com/en-us/troubleshoot/dotnet/framework/wcf/service-scale-up-slowly Could anyone can help

Important Note: This is application build on DotNet Core, Run on Kestrel, only call a Soap Service. Bad performance!

Thanks