Setting up replication

Hi,

We currently have an app with the database on the same server as the app
itself. I'd like to transition to a system where

1) in the short term, the db replicates to a different server. This will
allow us to take the daily pg_dump backups from the replica rather than the
primary server. They're currently slowing down the system too much as they
run.

2) in the medium term, switch the replica to be the primary and connect to
that from the app, i.e. app and db will be on separate servers, letting us
resource each appropriately. A 3rd server can then be used to replicate to
for backup purposes.

3) in the long run, depending on demand that also gives us the option of
scaling the db horizontally e.g. with a distributed db like Citus.

Are there any suggestions / good walkthroughs of how to do number 1? There
are many options!

All I know so far is we can probably use streaming replication as I can
make sure the PostgreSQL versions on each server are the same.

One thing I'm wondering is how often should a base backup be taken? Also
should we set up everything manually with scripts or use a 3rd party backup
tool like barman?

Any suggestions appreciated.

Oliver