How to increase AWS EC2 network connection limits?

Question

I'd like to increase limits of TCP/UDP connections on any EC2 instance. Is this hard coded and I need to switch to more powerful instance or is it possible to play with the network parameters?

Current setup looks like this:

   Client                  Load Balancer             Backend
 +---------+             +-----------------+         +---------+
 |         |             | 1001 open       |         |         |
 |   ----->| Port 1001   | redirect to 1002|         |1002 open|
 |         | -------->   |                 |  -----> |         |
 |         |             |                 |         |         |
 |---------|             |-----------------|         |---------|

I'm creating long-lived TCP Connections using websockets. Current limit is 3687 on t3.nano instance and I get limit exceeds on bandwidth in loadbalancer.

ethtool -S ens5 | grep exceeded

bw_in_allowance_exceeded: 40

I'd like to reach 5000 connections for example, without altering connection payload.