Ask their university or institute to provide them with some webspace and upload it there. It's their job to provide the scientists with tools to accomplish their work. Or apply for a EU grant or something for a central instance. I don't think it's sustainable another way because it's going to cost someone around $5 each month to keep 200GB of storage around. Say "many papers" is 15 and they're on average 200GB, that will be $800 a year someone has to pay (if my maths on AWS is correct).

Plain webspace or storage space has the additional benefit it won't get re-encoded or compressed by Peertube/Youtube. Depending on the exact use-case, other scientists might want to get the original data anyway. And some universities already have video portals, though usually for conferences, lectures etc.

Edit: Other than that there seems to be the TIB AV-Portal, not Peertube but pretty much what you're asking incl long-term archival: https://www.tib.eu/de/themen/wissenschaftliche-filme I don't know but I suppose scientific journals or university libraries might have storage available as well for attachments to publications.