We can monitor both AWS and On-Prem using Zabbix.

Solution 1: We can use AWS Template by Zabbix, It Available from zabbix 6.0 and above.

What Services can be monitored?

1. EC2 instances
2. S3 buckets
3. RDS

What Metrics? (Its uses AWS EC2 monitor metrics)

1. CPU
2. CPU credits
3. Memory
4. Volume
5. Network

How to configure?

Using AWS access key and Secret Key.

More About: https://git.zabbix.com/projects/ZBX/repos/zabbix/browse/templates/cloud/AWS/aws_http/README.md?at=refs%2Fheads%2Frelease%2F7.0

Solution 2:

1. Install Zabbix agent on (Remote) client machines.
2. Install Zabbix-proxy on same network.
3. Now Allow only Zabbix-proxy host to connect to your Zabbix-server network. (instead of allowing all remote endpoints)

More About: https://www.zabbix.com/documentation/current/en/manual/concepts/proxy