https://www.abyssapexzine.com/2021/04/dead-badger/
/humor, in case you were wondering.
(More seriously: this is great stuff, but it's on a desktop Mac Mini; I suspect getting it running on an iPad Pro might be just slightly harder ...)
On the iPad Pro that bootloader is locked down and running Linux on there is unfortunately very unlikely to ever be possible.
Unfortunately, “just” running code in kernel mode is incredibly hard on the iPad. There’s e.g. a hardware mitigation that turns a memory region to read-only and also only allows kernel code to run from this region. This mitigation is locked down and cannot be disabled once XNU is running on the iPad (http://siguza.github.io/KTRR/).
On top of that page tables are also protected by a “kernel within the kernel” (https://blog.svenpeter.dev/posts/m1_sprr_gxf)
Getting past all that is going to be very hard if not impossible.