Replication in sql server 2019?
Why is it omitted?

Because the replication NOT considered to be HA and DR solution, it is considered to be Migrate &amp; Load Data feature within SQL Server, which mainly cover the requirement of distributing subset of data into different locations wherein HA and DR solution mainly focuses on whole database/SQL-Instance level Failover capabilities.

Will Replication be deprecated soon?

I don't think whole replication feature will be depreciated, perhaps some sub-features of replication. for your reference..