For some reason, the embedded videos seem to break in Firefox Private Browsing (128esr). This had me stumped for a while until I tried it in a normal not-private window and it worked.
I'm using Firefox 139.0.4 canonical-002 Snap on Xubuntu, and the videos don't play for me. Even when not using private browsing, even when I disable uBlock Origin, even when I disable Privacy Badger (and, of course, I've set NoScript to enable JS for the tab.)
Do you have tracking protection on "Strict"? The player only started working for me after changing it to "Standard".
Oh, yeah, I am. I forgot about that setting. Switching Standard allows the videos to work for me, while Privacy Badger and uBlock Origin are enabled.