Remove the focus from an element after setText or sendKeys

It’s “reasonable” and you have reasoned it out very well.

But, there are caveats (see link below), as you’ve already hinted at. If your reasoning stands above all other possible solutions, then by all means use it (you might want to document that reasoning using // comments in the source).

That’s a great mantra/philosophy to work with. But since you are NOT modifying the AUT other than injecting JavaScript, in my view, it’s completely fine (I do it all the time!).