Of the sites you mentioned in that request, Instagram and TikTok embeds are not available to use on Dreamwidth because they use script tags. Our developers still need to look into why the Facebook embed code is not working. It should be whitelisted but it's possible that Facebook has changed their embed format to be different from what our whitelist allows.

I'm very sorry that this is frustrating for you. We have to individually whitelist each allowed embed site, and we can't allow embeds that use script tags because of security concerns.