Connecting several databases through a provider?

Hello,

I work as an independent IT consultant and have been commissioned by a customer to get his customer database in order.
This is really an enormous amount of work, because all data is stored on three different servers, which all have far too little storage space.
The customer wants to spend as little money as possible, as he is quite upset by the current crisis. But I told him that a cloud-based database is actually unavoidable nowadays!
I think that the Kafka program would be suitable for the customer, but it could also lead to the customer expanding and then he would have to start the whole work all over again.

My idea was to offer the customer the option of connecting several databases to each other through a provider like Aiven.
What do you think about this idea? That way you could always switch back and forth without having to worry about losing everything.

Hi,

A few questions so I can help give an answer:

What are the current problems with the customer database? Do the three different servers all have different parts of the database? Or different sets of fields for the same customers?

And is there a reason that you're suggesting connecting database together rather than merging it to have just a single database?

In terms of Aiven are you looking at the Aiven Kafka product? Or multiple Aiven products, if wanting to move to a full cloud database?