Php-fpm Nginx Config for 2000 concurent users for AWS ECS with 3 x 8core & 16GB Instances

We want to achieve 2000 concurrent users requests on AWS ecs with php-fpm & nginx combinations .

I am running 21 containers with 2gb across 3 instances of 8 cores & 16gb RAM on each instance.
My current Configuration is for www.conf:

[www]
user = www-data
group = www-data
listen = 127.0.0.1:9000
pm = dynamic

pm.max_children = 5000
pm.start_servers = 50
pm.min_spare_servers = 20
pm.max_spare_servers = 70
pm.max_requests = 0

With above config for 1000 concurrent users i get below result on Jmeter.
Transaction done is login-> view a page(heave page) -> logout.’

imgur

Source: StackOverflow