[Xiaomi Poco F3 / Xiaomi Mi 11X / Redmi K40] consoomer:
Hello, thanks for the OS! Working on Poco F3, coming from stock miui 14

The instructions are strightforward yet lacking detail, making the process look more complicated that it actually is. Here's what I ended up doing, follow at your discretion:

Preliminary: Unlock bootloader, install the adb tools for windows on the pc, unlink google account from phone (I recall having trouble with flashing in other phones if I forgot this)

In my case I use a bootable USB stick with Linux FWUL because I found flashing from windows unreliable in another phone, but it should be no different in windows environment because the commands are the same.

1. Boot into fastboot: reboot phone and hold vol down when poco words appear. "Fastboot" should appear on phone screen. Connect to pc. To see if phone is detected, open cmd.exe and type there:

fastboot devices

2. Flash the twrp recovery that comes in the OP post, download section. To flash, first extract the zip, there's an img there. I renamed it for convenience to 1stboot.img.

In my case, I opened terminal in linux in the folder that I extracted the zip to, this allows for simplified commads. It should be possible to do the same in windows by holding shift+right clicking inside the folder (in open space) and selecting "Open Powershell window here" option that appears in the menu.

Again, to check if the phone is detected, the same command as mentioned in step 1 is used, if nothing shows up, the phone is not being detected, a problem which is beyond the scope of this post. It can be a cable issue, a port issue, a driver issue, a windows issue or whatever. Assuming phone is detected, type:

fastboot flash boot_a 1stboot.img

fastboot flash boot_b 1stboot.img

If you're having any issue at this point, I reccomend installing a bootable FWUL linux OS on a spare USB and running the terminal commands from there. It's as easy as downloading an image and running etcher program. Just look it up on google.

3. Then enter the freshly flashed twrp recovery. Type in the powershell window:

fastboot reboot recovery

In my case, twrp appeared in chinese. select the 3rd rightmost option in twrp main menu (counting from up to down), then tap the small globe icon that appears in the menu that follows to change language. If you're having problems following here, look up pictures of the TWRP recovery interface menu on google.

4. Wiping data and stuff. Wipe > Advanced Wipe >tick first four options and swipe. I also used the format option in the wipe menu too, just in case.

5. Time to flash the stuff. To activate adb commands you need to: Twrp main menu > Advanced > adb sideload and swipe where it tells you.

To check if the phone is being detected and adb is activated: adb devices

To flash, first the firmware than comes in the OP post, in my case:

adb sideload fw_alioth_miui_ALIOTHEEAGlobal_V13.0.8.0.SKHEUXM_d7894a7a02_12.0.zip

Then the ROM, in my case the april 15th release:

adb sideload PixelOS_alioth-13.0-20230415-0710.zip

Just as before, the command is issued in pc terminal, opened in the folder where the zip files are. When I tried doing it the other way around, pixelOS didn't boot and I had to repeat the process, so do it in order. The whole zip is flashed, without extracting. I didn't tick the two options that appear in the menu, about cache.

OPTIONAL: The act of flashing PIXEL OS will wipe the twrp recovery and replace it with a stock pixel OS recovery. Just FYI, you're still in TWRP, but its files have already been deleted, the program is still on because it is loaded in the RAM, which will be wiped the moment you power off or reboot. To maintain twrp, use the "Flash Current TWRP" option before rebooting, especially if you want root. It is located in the Advanced menu, you need to scroll down. This is the only chance to get it working, When I tried flashing twrp after reboot, pixelOS stopped booting and I had to repeat the sideload process

Note: I don't remember needing to set active partitions, but better pay attention to the partition the os is being flashed to in the phone log that appears on screen during adb sideload process, and check if it corresponds to active partition in twrp main menu > reboot. You boot whatever partition appeared in the adb log during pixelOS flashing. Log is maintained until reboot and you can check it again by entering adb sideload and swiping.

6. Reboot and set up the phone os. I had no problem from here on. To install magisk, boot again into twrp recovery, advanced > Install Magisk, then complete the process when in pixelOS by clicking the magisk app that will appear in the menu. I had to boot pixelOS first, then reenter recovery, it failed when I tried it right after flashing the rom.

Note: I had display issues happening with youtube videos, both in miui and pixel OS, solvable by using "force max refrex rate" in display settings or using kiwi browser and enhanced h264ify addon to disable vp8, vp9 codecs (only works for the browser, in this case)