I don't want to sound mean and defeatist, but steaming service is very expensive to run due to the sheer amount of bandwidth and storage cost required. You can host standard website for free these days, but video hosting is another story.

Consider a standard 1080p video stream @ 16mbps. If your server has 1gbps bandwidth, you can only serve 62 people at the same time. You're going to need more and more bandwidth as your users grow or they'll get irritated and leave because your servers don't have enough bandwidth to serve videos to all of them (lots of buffering and timeouts).

So how much will those bandwidth cost you? If you plan to host them in a cloud provider, you should know that they'll usually charge by the amount of egress traffics you consume. If you maxed out a 1gbps link for a month in an AWS server, Amazon will charge you around $0.1 per GB, which means you'll get a hefty $32,400 at the end of the month for delivering 324TB of traffics.

Now AWS is literally the most expensive provider in term of bandwidth, so you might want to use a provider that provides unmetered billing. This usually means traditional colocation service where you buy your own physical servers and only pay for electricity and internet, or renting out dedicated servers which will cost a lot upfront but ended up being cheaper than pay as you go cloud providers. But you'll still looking to pay thousands $ each months to pay for the bandwidth.

Some pirate streaming sites cheats by uploading their videos into various cloud file storage such as Google drive and playing cat and mouse by constantly creating a new account and reuploading their videos when when their account for banned for violating tos. You might be tempted to go that route as well, but considering how you're already sweating at the prospect of finding and uploading all anime files yourself, constantly creating a new cloud storage account and constantly reuploading your anime files doesn't sound really great, right? Some pirate streaming sites literally have full time staff doing this stuff all day, constantly keeping up with new anime release, downloading them released schene torrents or ripping them out from Crunchyroll, then uploading to a cloud storage account or other video hosting services (and reuploading again if it were taken down due to tos violation).

I think this project is way too big for you right now, but pretty fun to think about especially the logistics part.