Hi Oliver,
To remove comments from existing pages, go to the “Pages” area in your Dashboard (or whatever post type you have), and click “Quick Edit” within the pages you wish to remove the comments from. While in Quick Edit mode, you’ll see an option to allow comments that you can de-select.
It’s important to note that if your page or post already has comments, disabling them like the above will simply stop new comments from being added. Existing comments and pingbacks will still display. If you wish to remove them, you’ll need to delete the actual comments or pingbacks from your installation in the “Comments” area of your Dashboard.
If you wish to disable comments on certain post types but not others (not have them on pages but do have them on posts), this plugin is great: https://wordpress.org/plugins/disable-comments/
Reference: https://docs.generatepress.com/article/removing-comments/