Not Changing Text with Block Theme

There’s no difference here in terms of how to set up the replacements, you just need to know the exact original string, textdomain and context.

You’ll need to find the original string in the plugin or theme code. You can check the FAQ (https://wordpress.org/plugins/say-what/faq/) or this article (http://plugins.leewillis.co.uk/doc_post/replacing-wordpress-strings-context/) for some examples of what you’re looking for.

Alternatively, the Pro version of the plugin provides a String Discovery mode which means you can search for strings on your site via autocomplete suggestions.
http://plugins.leewillis.co.uk/downloads/say-what-pro/