As Zabbix Agent 2 has proven itself stable throughout the release of Zabbix 5 I would like to suggest to change the installation instructions on www.zabbix.com/download

Right now throughout the versions zabbix-agent is still used in the installation instruction. 

For Zabbix 6 I would recommend to get users to install zabbix-agent2 by default, making sure no upgrades are needed in the future. If of course not already planned like this.