Or you could use Systems Manager (with Sentry) to fully control your devices, including providing an appropriate WiFi profile. With this option Meraki provides the X.509 certs and cloud RADIUS.
https://documentation.meraki.com/SM/Deployment_Guides/Systems_Manager_Sentry_Overview
If you can't or don't want to fully manage the devices (maybe they are staff-owned?) then consider Trusted Access
https://documentation.meraki.com/General_Administration/Cross-Platform_Content/Trusted_Access_for_Se...
Ether of these options will require you to purchase Systems Manager licences for the devices requiring connectivity.
You may still need to use username and password as an initial means of setup - after all, you still want to check what's connecting to your network to start with, right?