Question about Xiaomi Redmi Note 5

There should actually be one. At the moment it is on MIUI 9.5 (Android 8.1). The Xiaomi Redmi Note 5 is in the beta programme for MIUI 10 (Android 9) and should therefore also get the definitive version... But I wouldn't be too sure :-) After all, it is a phone from the cheap line (Redmi) of Xiaomi.
But honestly, who needs Android 9? After all, the Redmi Note 5, as a (more or less) full-screen phone, already has gesture control and no more home/back/menu buttons. And other "innovations" of Android 9 are already on board with MIUI 9.5... And I find the current gesture control of the Xiaomi Redmi Note 5 much better than that of Android 9 anyway ;-)