I haven’t done Ruby coding since… 2010 or 2011? But looking over the github repo for Discourse, it appears that the capability is just a pre-packaged plugin!
And, from the looks of the plugin code, it’s fairly boilerplate, using the OneBox Ruby Gem. It already has a module for Youtube, Vimeo, and tiktok. SO, what if we just copy-pasta the Vimeo one, and hack it up to make a Rumble version? Seems like it could work!