Multiple MySQL (masters), a database in each replication over VPN in a MySQL installation

I am trying to discover the best way to replicate data from multiple MySQL installations from different hosts to a central MySQL host. I was looking for a program or configuration that would allow me to achieve this. I've played with slave replication, however, the limit of a master stopped that idea. My current idea is to use slave replication in containers of the multi-instance MySQL docker. I want the replication to be live. So the databases dumps / restorations will not work. The problem with the idea of ​​the docker window container is the swelling caused by the execution of multiple (hundreds) instances of MySQL in several ports, to achieve this task.

Below is an image that tries to show an image of what I am trying to achieve. However, I only show three customer databases, I currently need to do this for more than 150 clients.

network desc

Any ideas?