Wow, that's a lot of embeds for sure!
If your thread is publicly accessible, would you mind sending me a link? I've tested the "lazy loader" with a couple hundreds of videos per page but I'm curious to see it in action in a real thread. That could inform future decisions related to real-world performance. Also, f you have a lot of YouTube videos in it, make sure you enable the lightweight placeholder option. (search for
ClickToLoad in the admin panel's search box)