Need to deploy Sophos firewall in AWS and use it for clientless VPN. Need licensing details of it

We are planning to deploy Sophos firewall for clientless user VPN and allow users to RDP/SSH to servers behind the firewall. There will be around 2000 concurrent users.

Please share the details of licensing required to support 2000 clientless VPN users and also the instance requirements.

Thanks,

Lohith