[Magisk] pndwal:
Being Xiaomi, patching boot.img will most likely work despite Ramdisk=no. If your previous successful Installation was installed using zip archive flashed from TWRP, this would confirm Magisk in n boot partition succeeds on your device as zip necessarily installs to boot ramdisk, even if Magisk has to add it. (Works for me -RN8T- and for other models/users also). See below.*

Method:

Select Install Magisk, deselect Recovery mode, Patch boot.img, flash to boot partition using fastboot.

It's not clear what you first did. If you tried direct Install to update, you MUST unhide /restore Magisk Manager/app thru settings menu if hidden/renamed as clearly stated in the changelog (due to new incompatible hiding method) BEFORE updating Manager/app.

If you failed to do so, you likely had working root, but app shows 'n/a' due to the two apps conflicting. You need to uninstall BOTH newly installed app AND renamed (hidden) Manager, before installing app again.

Seems you may have Magisk in recovery partition now also (not sure whether you still have patched boot.img). - To get rooted OS depends on boot method in this case. Did you thereafter (starting from power off):

Use Recovery Key Combo, → (Splash screen) → Release all buttons (to get System with Magisk)?

Nb. Power up normally (= System with NO Magisk),

Recovery Key Combo → (Splash screen) → Keep pressing volume up (= Recovery Mode)

Also, your error message suggests archive download is corrupted, and this may be causing other issues too. Or, if you were still using Magisk patched recovery, this is a likely cause as you CANNOT use zip installer to update Magisk in recovery partition. You may also have TWRP incompatibilities, which is common, and why recovery flashing has been consigned to 'Legacy device support'.

I'd recommend cleaning up conflicting Magisk app/manager(s) as described above, flash clean / unpatched boot and recovery images, check system and recovery now boot normally, Install latest Magisk app, then try recommended patching method I described at the outset, but w/ boot.img, not recovery.img.

*Regarding Ramdisk=no

The current Installation Instructions say:

"if the result is **No** this means your device's boot partition does **NOT** include ramdisk. This means you will have to go through some extra steps to make Magisk work properly."

However, there are exceptions to this where patching and flashing boot image (as if your device's boot partition does include ramdisk) works because the assumption that bootloader is incompatible where OEM doesn't supply ramdisk in boot partition may not be true.

Magisk will add needed ramdisk functionality to boot image where lacking, but Magisk app will continue to indicate factory ramdisk state, ie. 'no', to indicate that bootloader support cannot be relied on. The only way to know for sure whether bootloader does or does not support the Magisk-added ramdisk in boot is to try patching / flashing boot image. Notably, this will work on most recent Xiaomi devices.

While Magisk should install in recovery partition by patching / flashing recovery also in these cases, installing in boot will be a better alternative.

If your bootloader does not support boot ramdisk, Magisk must be installed to recovery. Read the Magisk in Recovery section for VERY important information!

Hope this helps. PW