Well, installed today this update to Mi5s. I was waiting a little bit because the last info I saw here at the thread about the problems.
First of all, I updated twrp via it's official app, once it was updated I rebooted the phone and installed the ROM manually via twrp.
1- wiped dalvik and cache
2- installed ROM
3- wiped again dalvik and cache.
Reboot
It took a long time to start, and one time it started, the battery dropped faster from 90% to 52%, in .... 1 minute
I left the phone without touching anything, just it has to fill the cache and all the rom needs.
5 minutes later, I rebooted again the phone and installed magisk 17.2, via twrp too.
When it started again, the phone was faster than ever!, I plugged the phone to charger and waited to be fully charged.
Everything seems to work fine, no problems detected, and the battery life (for now) it's a lot better than before, at 15:00 I usually have a 51% of battery left, today I have a 72% !
I must wait some days to see if this is real.
Phone is cooler than before (working with it), and a lot faster (I switched on the experimental features in options about pre load apps and so).
Thanks for the ROM, it's quite perfect for me.