Hi jim
802.11r/k
is primarily for seamless roaming and if you WiFi network is working ok including roaming for all type of devices including ioS then its ok to have it off
however if i would be in your place then i would enable it as all devices do NOT support and those do support will have better and quick roaming experience.
apple device by the way support 802.11r/k
so better to have it ON...
read -
https://support.apple.com/en-in/HT202628Hope this helps in making better decision...