Simply adding a reply as this was interesting. As Vasil says the ODFB or SPO size matters, but I have not heard of that issue previously. To be able to upload in chats you need the license for it. If users aren't assigned SharePoint licenses, they don't have OneDrive storage in Microsoft 365. File sharing works in standard channels, but users won't be able to share files in chats without OneDrive storage in Microsoft 365. Keep us updated :)
www.000webhost.com