My autistic two cents about holoalternative. If hololive tries to make an twitch/youtube alternative they will fail miserably, on the west at least.
People understimate on how big youtube/twitch are, how big is their network effect and how hard is to run a streaming service.
For the network effect for example, you can easily move loyal fans from platform X to platform Y but if you watch youtubers who are more transparent about their channel, you will see that a lot of time most of their viewers aren't subbed or subscribed this alone reduces their channel growth by a good margin as those people wouldn't be interested into creating an account and downloading a new app to watch a streamer.
About being hard to build, there's two points to consider besides creating the platform. The first one is the laws, if cover puts the company on Japan, be ready to have a worst platform that youtube and twitch as their copyright rules are way worse than US.
Second is delivering the content, while they rarely shows, from time to time a big vtuber shows her viewer country list and about 30-50% of them are from small/third world countries, unlike Google and Amazon that has servers in almost every country, Cover wouldn't have money to put a CDN in every country like them, this would make(like NND) that the stream to be sttuterry, laggy and slow. So while it could work on JP because of their culture, I doubt a bit in the west