You can disable Comments on Pages and Posts in Bulk. This article should be helpful for you: https://www.wpbeginner.com/wp-tutorials/how-to-completely-disable-comments-in-wordpress/#:~:text=To%20do%20that%2C%20go%20to,on%20all%20your%20future%20posts.

It looks like our site will be moving to a different platform, but we’d like to keep the current site as an archive, which means we’d like to disable new comments being added to the site.

Is that possible?

thanks,

Paul