Airport express router security

The best that you can do with the AirPort Express, security wise, is the setting of WPA2 Personal, combined with a long password comprised of random letters and numbers.

Unfortunately though, the longer your password might be, the longer it will take devices to connect to the Wi-Fi.

The "best" WPA setting is WPA3.....but the AirPorts are not capable of this. WPA2 should be OK for most users on a home network if they are using a long password comprised of random numbers and letters.