In my experience, I bought some pro/high sellers/high rated themes on Theme Forest for 3 sites, but all of them come with a bunch of pre-installed plugins, and was a mess.
Specially two who have a mandatory plugin to edit pages, called WPBakery, damn I hated it, is awful, the native WP editor is miles away (Gutenberg), but the design will brake if you use Gutenberg. Also, this and other plugins do not auto-update automatically, for each update you have to login to a site of the theme seller, download a zip, and update the plugin manually. And also on the admin you always gets upsells of the pre-installed plugins all the time, you can't disable it, sometimes you get a rack of 3 top banners simultaneously.
The end user sites looked really nice tho, but the editing experience was horrible.