I couldn't find any option to edit my category pagesYou mean category page? isn't that option in your theme? I mean theme option to customize it.
Yes, I can add a description, but I'm looking for more editing options, such as those offered by Gutenberg.I never saw a theme that doesn't allow to edit category under the post s -> categories but some don't show the category page description.
The categories pages can be created in post page section. While Writing the post then at right side bar in WordPress You observe the categories
you can go with post pages as a category
These are the steps to edit the category pages in wordpress.
Step1:Go to Posts > Categories.
Step2:Find the category name you wish to change and click Edit.
Step3:Change the category name.
Step4:Change the category Slug, the permalink “nice” name for the category.
Step5:Add or change the category description.
Step6:Click Update.
You can manage WordPress Categories and Tags by hovering of the "Posts" menu item in your admin area and then clicking on either Categories or Tags. Once in either the Categories or Tags management area you can create and delete categories or tags. You can change their 'slug', which is just a funny name for the URL where they are found. You can also add a description. The descriptions are used by some themes, but not all of them. So there's a chance that you'll add a description and no one will ever see it. You will also be able to create categories and tags on the post creation page. When you are creating a post you will see a Categories Meta Box and Tags Meta Box on the right hand side of the page .To assign a category to a post simply click the check box beside the one you want. If the one you want isn't there you can create one