First of all a big thank you for all the information, with the version of MIUI you mentioned above i was able to unbrick my Redmi Note 5 AI china version phone (installed with a global ROM by the Ali Express seller).
And were you able to unlock your Xiaomi RN5 bootloader and install the new MIUI 10 Global update (not chinese/ india/ russia) with Android Pie i.e. V10.3.1.0.PEIMIXM (MIUI10) from here - http://en.miui.com/download-342.html#508
Also, if may i ask you; what version of Redmi Note 5 do you have.
Is it Redmi Note 5 AI china version or global version or a Redmi Note 5 Pro Indian version ?