How to ensure fault tolerance?

Question

linux

Hello!
There is a server running postrgesql10 and redis4 . Postrgesql10 is configured to logically replicate some tables asynchronously with another server. The server is the key, since 3 applications work with these databases, you need to provide fault tolerance. It was decided to put next to the same backup.
What solution can be applied? I tend to multimaster replication.

Answer 1

What does not suit the standard option with a replica, auto-promotion and moving the vIP to it in case of a disaster?