I'm seeing this too. I noticed that switching to just sae (WPA3) or pure WPA2 makes the respective Apple phones and tablets connect without any issues.
Some googling hints that this is only problematic when WPA2/WPA3-mixed mode is combined with enabling extensions like 802.11r/802.11k/802.11v. These are needed to implement Wi-Fi steering (aka seamless roaming). You'd normally enable them when you have several WiFi APs. So it's understandable why not everybody is able to reproduce this issue.
FWIW I blame Apple as there seem to be other AP firmwares/vendors having this same problem with portable Apple devices.
Context:
- https://www.reddit.com/r/RuckusWiFi/comments/tuxgyn/r710_ios_devices_will_not_connect_when_wpa3_is/i3724h3/?utm_source=reddit&utm_medium=web2x&context=3
- https://www.reddit.com/r/RuckusWiFi/comments/tuxgyn/r710_ios_devices_will_not_connect_when_wpa3_is/i38hekd/?utm_source=reddit&utm_medium=web2x&context=3
Also, other places on the internet suggest that some devices can't stomach WPA2+WPA3 mixed mode: https://help.keenetic.com/hc/en-us/articles/4402854785170-Why-can-t-my-home-network-device-connect-to-the-Wi-Fi-network-.
P.S. I haven't yet verified experimentally if disabling those Wi-Fi extensions helps. So take it with a grain of salt.