Meks

This is a simple plugin which automatically hides inactive (orphan) shortcode tags you have used for previous themes and/or plugins. It uses the_content filter to search for shortcode tags which are not active and simply removes them from your post/page content (note the shortode tags won’t be deleted form your content, they will just be removed temporarily on your website frontend). It is a great solution if you want to avoid manual removal of old shortcode tags from your entire content.
Remove Orphan Shortcodes plugin is created by <a href="https://mekshq.com" rel="nofollow ugc">Meks</a>

Remove Orphan Shortcodes

Any gutenberg block storing an array in block attributes JSON is flagged as a shortcode. As most blocks using JSON attributes also use render_callback and server-side rendering, this causes the block to disappear entirely - broken JSON is hard to parse.

Ergo, don't use this if you also use ACF, because any repeater or relationship field in a block can cause the entire thing to disappear.

Fails with Gutenberg Block array attributes

Quickly remove unused (orphan) shortcode tags from your content.

Samuel Wood (Otto)

The normal Text widget allows you to insert arbitrary Text and/or HTML code. This allows that too, but also parses any PHP code in the text widget and executes it.
This can make it easier to migrate to a widget-based theme. However, this plugin should not be used long term, as anybody with access to edit the widgets on your site will be able to execute arbitrary PHP code.
All PHP code must be enclosed in the standard php opening and closing tags ( <code><?php</code> and <code>?></code> ) for it to be recognized and executed.
Only users with the unfiltered_html role will be allowed to insert unfiltered HTML. This includes PHP code, so users without admin or editor permissions will not be able to use this to execute code, even if they have widget editing permissions.

PHP Code Widget

Simply Awesome !!! 

WHY IS THIS NOT IN THE CORE, AND WITH THE ADDED FUNCTIONALITY TO EXECUTE PHP IN THE EDITOR???

No, instead we waste our time with useless Gutenberg !!!

Thanks for the plugin, it is a time saver for me. I can put the code in a widget, and display the widget in the content area via a shortcode... does the job well.

Unfrieking Unfreikingbelievable !!!

No highlighting for snippets.Support also doesn't exists. You can find much better plugins to insert php code snippets

much better solutions

Like the Text widget, but also allows working PHP code to be inserted.

Remove Orphan Shortcodes vs PHP Code Widget