@ingbrzy
Device: Mix3 (Perseus)
Dirty flashed the latest stable v12.0.3.0.QEECNXM from last weekly 20.9.4 of September. The device boots to lock-screen for 2 seconds and then reboots to TWRP. It's not a crash reboot as the reboot animation spins for 10 seconds as if some function is calling...
On Mix 3/Perseus, Messaging app crashes when text is entered in Search bar or SMS app. Also default editor in Gallery crashes when editing studio lighting pictures on the Mix 3.
There is no way to change the swipe up action on default launcher. I suggest you try a 3rd party launcher that might have this functionality. Sadly, OK Google doesn't work on any MIUI ROMs based on Pie :(
Would like to know if there is a option to modify the icon grid size on the Mix 3. It doesn't let the theme apply custom grid size like previous devices and keeps it fixed to the size set in Home screen & Recents setting menu.
Now this is the same custom theme applied in Redmi Note 4x...