Retain Microdata Code Toggling Between Views

I need to add Schema.org microdata to multiple locations pages for a client’s site.

In HTML view I can enter:
<div itemprop=”name”>Name</div>

However, when I toggle to Visual view, and update, it strips out all microdata code to just <div> or <span>.

I know there are multiple plugins available for adding microdata, but none of them do exactly what I want, plus it’s a lot more time-efficient if I just do it myself. So those are not solutions for me.

Also, manually editing the TinyMCE files won’t work, because I do not have access to them, and I believe they will get overwritten when there’s an update anyway. I saw this post here, that would probably do the trick: https://snipt.net/jamesw/prevent-tinymce-from-stripping-schemaorg-attributes-in-wordpress/
However, I do not know where to place that code, if I can, since I do not have backend access to those files.

We do have TinyMCE Advanced plugin installed, but I’m not sure if this is a solution. I’ve spent hours searching on the web to try to fix this, including extensive research on this forum, and I’ve come up with nothing.

Please help!