Hello @Slash_J, and welcome to the forum!
You want to know what your issue is? Okay, it is called:
Or, to be precise, it is the OS, the operating system your device runs with. Even if you would make handstands jumping around your “XP pen magic drawing pad”, it will never render an animation with Krita in the foreseeable future, because Android disallows non Google applications to communicate together and exchange/share data, in other words Krita and FFmpeg are disallowed to exchange the animation data.
You have at least two options:
The first and most simple one is to copy your KRA-File with your animation to a PC or Mac running Krita and render it there.
The second option is to render your animation on your device into a sequence of pictures, and then take this sequence of pictures and stitch it together with a video editor capable of creating videos from pictures. Years ago, there were enough apps for Android capable of doing this, so I guess you should be able to find such an app. There are also standalone FFmpeg versions for Android able doing it, if you do not fear the often unfriendly way to use FFmpeg (command line style), you will have the most powerful tool at hand.
The third possibility is for well versed computer users, for people who love a commandline interface and do not fear to deeply fiddle around with and on their device. If you believe to belong to them, then you may want to try the way described at the end of this topic:
I really don’t understand why XP-PEN didn’t use a mature operating system like Linux or Windows for such a sophisticated device as yours! At least if I ignore the fact that Android is cheap junk sponsored by Google, which allows such a device to be offered at a bargain price. However, this comes with unpleasant side effects, which of course are not mentioned in the glossy advertising with which XP-PEN celebrates this product.
And this where Linux also costs nothing except the necessary expertise, and Windows is also being sold off cheaply.
I feel sorry for you.
Michelist