I upload a link to the bilibil video, but it's not an embedded video.

Well as long as the link works it should be fine for most purposes. Embedding is really only supported for the standard sites (YT & Twitch), since they're the most common.

Bilibili videos were embedded in the past, but currently there is a bug in the site that prevents it.

Just wanted to update this, this is how to embed Bilibili videos on speedrun.com currently: https://imgur.com/a/hsMnX5X

Mirror link if imgur is down

No VPN's or downloads etc required.

I still can't download the Bilibili video. bilibilivideodownloader.online/en/