Xiaomi's latest build of MIUI 11 for the Mi 9T and Redmi K20 may be re-issue Android 10 to both devices, but there have also been reports of the update causing heavy battery drain for some handsets. There is a workaround though, with some Xiaomi software potentially being at fault.
https://www.notebookcheck.net/Android-10-builds-of-MIUI-11-may-cause-high-battery-drain-on-the-Xiaomi-Mi-9T-and-Redmi-K20-but-there-is-a-workaround.451770.0.html
I havec also facing terrible SOT and very big battery drainage since android 10 i installed... I barely achieve 4-5 hours SOT on wi fi usuge trough the day... I really hope Xiaomi updaate will solve thise use soon
Interesting, because in my case the battery drainage has been reduced. Battery now lasts me between a day and a half and two days of my normal usage. Before it was impossible to get to two days.
Although I have seen an issue: the "always-on" screen notification isn't working when I receive a Skype message. Though I'm not sure if it's a problem with Skype on Android 10, a problem with Skype on MIUI 11 on Android 10, or a problem with MIUI 11 on Android 10 with non-system apps.
Anyway, for now I'm a happy Mi 9T Android 10 user.
I received a notification that there was an update to download which would change the Mi 9T from Android 9 to Android 10. I put it off for a couple of days and the notification disappeared so I'm still stuck on Android 9. Reading that I'm glad I am, I don't have any issues with Android 9 and everything works perfectly so if it ain't broke I'm in no hurry to fix it.
I'm still waiting for the update in Pakistan. I hope they release it soon