He always used Enlighter and not dealt with Gutenberg, but it's time to move on it.
Here's what it says in the description of the plugin enlighter -
Gutenberg Full Editor Integration
In fact, it should fully work correctly with Gutenberg
also found an article - https://wptavern.com/syntaxhighlighter-evolved-plu...
Try this plugin too 0 https://ru.wordpress.org/plugins/syntaxhighlighter/