My first advice would be to move all non-IoT devices to WPA3-Enterprise (802.1X).
For PPSK (named iPSK in the Meraki World), I still hope that Meraki will implement "iPSK with RADIUS" with WPA3 on MR APs. All other vendors, including Catalyst Wireless, are capable of that.
But typically, I keep IoT devices on an iPSK SSID on 2,4 and 5 with just WPA2. Many of these devices can't connect with WPA3 anyhow.
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