Using copyleft without heavily restricting what platforms to share on
Is there a way to release a work under a copyleft license without preventing other people from sharing a copy of it on YouTube (only allows selecting standard YouTube license or permissive Creative Commons license) and similar platforms?
Copyleft licenses require that derivative works maintain that same license. Not all the Creative Commons licenses are copyleft. CC-BY only requires that attribution be given in the derivative work. That's the one YouTube offers as an option for uploads.
As I say using copyleft work on other platforms is doable. On YouTube it's doable if you make a derivative work, but on peertube ou dogmazic.net for instance it is perfectly fine.
But as I say maybe I understood wrongly the initial question...
I'd say to ignore the platform licensing and just make sure that the license appears in the media itself (which it should, anyway, in case anybody finds it randomly) and marked in descriptions.
YouTube seems interesting, because there's so much garbage listed as CC-BY that almost certainly doesn't have any legitimate permission for it, and I've never found actual Creative Commons content through that route, so that probably informs my "just ignore it" thinking...