Full disclosure: I haven't been inside an idevice since iPhone 4S, and neither eye-sight nor dexterity has gotten better since, but this operation IMHO most definitely deserve the "difficult" label. Apple had told me that my USB-C port had rusted [sic!] due to humidity and the only repair was a replacement at almost the price of a refurbished (but with much less warranty), so trying this was a cheap investment. I got it open, replaced the port and reassembled, but at the cost of a cracked screen (step 23 is quite tricky), and the patient still wouldn't charge. It's satisfying proving apple wrong (that or the spare I got was broken, ifixit didn't have one, so I had to turn to ebay, which is a lot less reassuring), but if you can't afford to lose your ipad and aren't particularly skilled with fragile mechanics, consider professional help for this. The guide is most excellent, any blame for my cracked screen lies squarely on me and I don't regret trying.

This (step 23) is by far the hardest part, the glue, even in warmed-up state, is quite strong and the panel extremely fragile.

Same(ish) question as Keyman: why not steps 1, possibly 3, then 11? Why disconnect everything if the SSD is fully exposed when the bottom comes off?