Bashibazouk, before you do this, do you have enough bandwidth and drive space to host videos? Videos do take up a lot of both.
I belong to a group that video records our meetings, and then set up a members-only area for those videos. The way they’re handling them, though, is to post them as Unlisted on Youtube and we log-in to our member accounts on the group’s website, then we can watch the videos on our site. In order to ChromeCast that video, you have to open the video in YouTube by clicking on “YouTube” in the bottom right corner of the player and choose “Open in Youtube_ and it’ll open in a separate Tab. Even though the video is Unlisted, we can still ChromeCast to the TV from that tab or window.
If you do have enough bandwidth and space to host your videos, I don’t know how, but I did find this link that explains why you shouldn’t.
https://www.wp101.com/10-reasons-why-you-should-never-host-your-own-videos/
Hope this helps and good luck.
Mathis…