Follow what show on device, should be ... Step 1/2 -> 2/2, then flashing ended, can reboot device in system. (In cmdline: If the process succeeds the output will stop at 47% and report `adb: failed to read command: Success`. In some cases it will report `adb: failed to read command: No error` which is also fine!")
If you want install separate gapps on vanilla buildtype, after flash ROM:
Attached is a zip containing a new boot.img and also a new dtbo.img, the dtbo isn't really necessary but I updated it to match the panel settings in the stock MIUI tree. In a dark room, the always on display might be quite bright but it's actually using less power than it used to.
You can check the power usage with the display off by connecting adb over wifi and looking for lines like this in the kernel messages:
It's the c= number that's important, this is the power consumption. With the display off it's about 17K, with the display in low power mode it's about 40K and without my fixes it was over 100K with AOD on.
This boot.img is patched with magisk, has root and should pass safetynet.
You can also try the kernel out using:
fastboot boot boot.img
Unplug usb quickly after it says it's booting or it will just show a charging icon. This won't modify your system, just reboot to go back to the original kernel.
All this should be quite stable but because the system wasn't previously going into suspend it might show up other bugs in some drivers. Use at your own risk!