Hey @magicmark thanks for getting back to me!
I actually figured out what was going on - it turned out that the videos worked perfectly fine on other Windows computers. So the issue was isolated to my own setup.
After some digging, I came across a 2022 article mentioning that background videos in Windows may not play if the “Show animations in Windows” option is turned off in the system settings. And that was exactly the case on my computer.
After re-enabling that setting, the background videos started working again without any issues.
That said, I find this a bit concerning. I have no idea why that setting was disabled on my system - but if it happened to me, it could easily affect others as well. It’s unfortunate that this Windows setting can completely stop videos from playing on a website.
If anyone knows why this restriction exists, or if there’s a reliable workaround to ensure background videos always play regardless of that setting, I’d really appreciate any insights. It’s definitely something worth understanding better.