Comment by Tmpod

Well, I can't check if it is still a thing today, but Element's managed servers used to allow you to do that, at least for the web app (though I had the idea they also did that for the old mobile apps?)

Here's a couple of links:

https://element.io/blog/custom-branding/

https://element.io/blog/a-white-label-messaging-app-to-creat...