Hey there!
I'm uploading my game to a drafts page, and when I go to upload the .zip with index.html in it, the dashboard treats it as it would a windows executable file in that I can't click "this file will be played in the browser" despite having done this multiple times for multiple other projects.
I've looked around the Unity forums and haven't seen much about this issue. It's very likely that it's something dumb on my end so feel free to be like, "you're dumb".
Thanks!