I dirty flashed over eu 9.27 V3 ( Android Q).How long did the update take when you updated? I used TWRP to install the latest Revolution Rom android 10 update for Mi 9 and 20 minutes has gone by so far and my phone is still updating. I am updating from the latest Revolution Rom android Pie update.
EDIT: Looks like I am going to have to do a clean install.
It took a few minute as usual.
I hope everything ok for you now.
Inviato dal mio MI 9 utilizzando Tapatalk