@IainP you should have no problems as you are separating the WiFi5 and WiFi6 APs.  If there is signal bleed between the floors that causes any issues, then you can disable the WiFi6 features on the MR46s.  However this is not likely to cause problems.   There are some devices that have problems with WiFi6 APs, the ones I know of are older Intel drivers that do not see WiFI6 APs at all (from memory about 4 years old+) and Realtek cards in Windows 11 devices.  The former is simple to fix by installing a newer driver, the latter might need a downgrade to Windows 10, or a swap to a different card.  ... View more