Here’s a quick tip on flowing anchored objects:
https://creativepro.com/auto-reflowing-images-in-a-grid.php

Do you think something is wrong with the QR code generated from InDesign on the Mac? Or something wrong with the iPhone reader?

Yes, I think this is a matter of choosing a different font. Alternatively, you could apply a grep style to make the character larger and lower the baseline shift!

If the word is actually typed in all caps (as opposed to having the All Caps style applied to it in InDesign), you could search for it in the GREP tab of the Find/Change dialog box with this: ^\u\u+?
That means “a cap at the beginning of the paragraph followed by 1 or more cap letters”

Then in the Change To field, just type $0 (which means “replace with whatever you found” and then apply a paragraph style in the Change Format area of the dialog box.

To find paragraphs that begin with words that are not all caps, use ^\u+ (that’s one uppercase character followed by one or more lowercase)

I’m sorry to say that Lynda.com took it down! That’s sad. I’m going to contact them to see if they will reinstate it.

In general, it’s best if you use File > Place. But if you don’t like all the stuff it brings in, then turn on Show Import Options in the place dialog box, and then you can control what does and doesn’t get imported.