My advice is to use Perforce and follow this guide: Using Perforce as Source Control | Unreal Engine Documentation
what you have to do is rent from a cloud provider (Amazon or Microsoft) a virtual machine, then connect via remote desktop, install perforce server and open the related ports.
You could do the same with Git but not really on GitHub, I’m pretty sure there is a limitation on how big each file/project/repository can be (in terms of file sizes).
What you could do is to sync the project files with github but use other ways (like google drive) for .uassets files, sadly .uasset is an overused and propertary extension in ue4 and not really compatible with any source control, so you can’t really achieve any good source control setup as far as I see it
p.s.
in the link above there are also the extensions needed to be sync, so if you need them you can take the list from the perforce guide even if you use git