Creating an interactive Streaming Platform on our Website

Hello! My business partner and I are looking to see if anyone is able to help us with our project: we are looking to host an online festival/ fair with vendors that will have multiple live streams happening at the same time and we would like to have a program or platform created where: -- Customers can choose between multiple live streams that are happening simultaneously (up to 10) embedded on our website through Youtube streaming -- The ability to have up to 10,000 viewers (what would this require from our server/website?) -- There is some form of a chat function for participants to interact with the live stream (comments, questions, etc) --The ability of us (Admins) to post Banners/ announcements in the live chat -- If its possible to have group/ friends together in their own chat rooms with a certain code upon registration -- Given that some of the live streams are going to be displaying inventory and educating about piece, we want to be able to integrate a "buy button" that would link people to our Square or Shopify inventories We already have the website and are looking for an experienced Web developer/ coder who can assist us with this project as we are wanting to see if there is a way to have this created on our website as opposed to having to host the event through Youtube or Zoom, for example. We are looking for someone who is able to create something custom and rather extensive - and someone who can work with us to reach an understanding of what we are looking for. The criteria listed above is our ideal, however depending on how difficult or time extensive certains components are we might be able to pick and choose the most important features to have (say 5000 participants viewing instead of 10,000). As we have less developing and coding experience, we are wanting to know what the scope and timeline would be for a project like this. Happy to answer further questions or provide more details regarding what we are envisioning/ hoping for and looking for a great match for this project. Thank you so much! Best, Madison C. (The Gem Fest)