Which tool? 50 concurrent users each with a unique client cert (UI or API)

Manual concurrent user testing is bad! But I am having a hard time finding a tool which will allow multiple concurrent users each with their own client certificate. Currently we are running multiple instances of JMeter each with a single certificate loaded. This is not really very scaleable in the event that we need to increase the User load.

Any thoughts / ideas will be greatly appricated as I cant believe I am unique in this requirement.

Locust io supports client certificates, uses python.
https://locust.io/

Gatling supports configuring a specific KeyManagerFactory for each virtual user, see https://gatling.io/docs/current/http/http_protocol/#keymanagerfactory.

@ian808 you can refer https://club.ministryoftesting.com/t/performance-which-testing-tool-and-why/634/24 where its clearly mentioned about different variety of tools with pros and cons.