here is a good start
the Agent UCIfied
the template for the server
https://pastebin.com/nQdZM89w
here is the default config for the agent.
config zabbix_agentd 'zabbix_agentd'
option AllowRoot '1'
option ServerActive '192.168.0.100'
option EnableRemoteCommands '1'
option Hostname system.hostname
option Include '/etc/zabbix_agentd.conf.d/'
option LogFile '/var/log/zabbix.log'
option Server '192.168.0.100'
option StartAgents '1'
if you want to do Active check (line ServerActive) or Passive check (line Server)
Active is router send info to zabbix server
Passive is zabbix-server grab data from router.
choose what you prefer.
Zabbix Agent can't do everything, but you can learn him how to be better.
if you check /etc/zabbix_agentd.conf.d/ you will see some files i call "extension keys"
example, : UserParameter=wifi.iwinfo.channel[*],lua -l iwinfo -e "print(iwinfo[iwinfo.type('$1')].channel('$1'))"
zabbix agent don't know how to check a channel. but with this key in the server "wifi.iwinfo.channel[wlan0]" the agent know what to do for checking the channel of wlan0
so you can create your own custom keys.
but don't forget to don't perform all the templates check just for know if an AP is here or not.
perform a simple check as i explain upper, every minute, and grad more infos every 5minutes / 10 minutes / hour ? day ?
maybe you can tell your AP to send how many people are connected every minute. but not all data.
good luck for you configuration. (and i you need help, ask)