This does not work unfortunately.
The idea is good to use RTL content to show the RTL support.
But you change the generated HTML file and not the source file, your changes would be lost with the next update. The source file is here: https://github.com/tabler/tabler/blob/dev/src/pages/layout-rtl.html

And I don't think it can be fully translated without a lot of changes for this single use-case.

You would have to traverse through all Jekyll templates, layout and include files and make them translatable somehow.

What you could do is to change the page-header and page-title variables in the linked file.