I would suggest that all main social site content creators should upload their content to the alternative sites like d.tube, bitchute, gab, minds etc. as well as their usual sites.
Then over a period of about a month or two, provide the links to their work on these new sites, clearly on youtube/twitter/fb etc. and encourage their audience to go to their content on these new sites, to get them to experience these sites and consequently spread the word.
You could for example cut some of the more "controversial" material out of the youtube/twitter version, and preferably in subtle ways, inform your audience that the un-redacted versions are only available at these new sites.
Also download all your content and all related data from youtube etc. if you don't already have a backup version of it.