Get the latest APK from its official web ( https://github.com/topjohnwu/Magisk/releases ), notNOT from Play Store.
IMPORTANT NOTE ABOUT FUTURE UPDATES OF MIUI:
[updated 2024-02] If you accept any of the MIUI OS updates, your rooted init_boot will be replaced by the update, your tablet will stop being rooted (no morethe apps that need a rooted device will stop working properly) and you will have to repeat the steps from here. Although one could argue that it should be from point 3 to be fully correct. I just did it from here (I didn't care about the changes made by the update) and it went well (may not be always like that, be warned).
END OF IMPORTANT NOTE ABOUT FUTURE UPDATES OF MIUI
