I want to ask why in the Site library you have some sites like lets say Merch where you import Gutenber Plugin , i want to say Gutenberg is not installed in the wordpress ? is different the plugin itself than the core edditor ?
And if this is imported for older wordpress versions , should i not import gutenberg plugin if i have the new wp versions
All updates to the Block Editor are released first in the Plugin.
This happens around every 2 weeks.
Around 6 weeks later those updates are added to WordPress core.
Which means the plugin is always a couple of versions ahead of the core WordPress editor.
In the early days of Guteneberg the core editor had many bugs and was missing important features. So the plugin was necessary. Its less of an issue today and any of the current Site Library sites will be fine without the plugin.
Personally i keep the plugin installed as bugs are still being fixed, improvements are being made and it allows me to test for plugin compatibility or other issues.