Hi,
Considering what you said, there are some possibilities.
For internal users, you can consider using 802.1X/EAP authentication methods1. This method is more secure and has replaced some outdated methods that have security weaknesses. You can also consider using multi-factor authentication methods to strengthen security while continuing to prioritize usability.
For guest network, you can create a separate VLAN for your guests. This prevents unauthorized access and associated security issues by isolating guest devices from the internal network.
For a BYOD network, you can consider using the same 802.1X/EAP authentication methods as your internal network. Additionally, you can use Single Sign-On tools that let employees use a single password to access a portal of company and cloud applications.
Of course, this is just a general recommendation, there are other options like Meraki's MDM.
https://meraki.cisco.com/products/systems-manager/
I am not a Cisco Meraki employee. My suggestions are based on documentation of Meraki best practices and day-to-day experience.
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