So, today I tried this same procedure on my other blogs and it just didn't work. WP iOS failed to update.
So, I messed around with it a little bit and found a solution that did work:
From the WP Dashboard go to Security > Tweaks and turn off every setting and save each section as you go except forWrite to WordPress Core Files. Make sure this option is selected.
Now, starting at the top of the page, select all the options you want. And save each section as you go down the page.
I selected all the options expect the very last one, Turn Off file editor in WordPress Backend. And iOS worked for and updated all my blogs.
For some theme slider image problems, I needed to leave Filter Suspicious Query Strings unchecked. But that didn't affect iOS.
Order matters. I once scripted htaccess files. But that was a decade ago. And I'm too rusty to sort it out tonight.
Hope this helps. I'll see what happens tomorrow. :-)
Regards - Dennis