Hi, @Eugene Zheganin Welcome to the Microsoft forum, thank you for posting your query.
Any chance that you can migrate to flex?
About single, the only option is logical decoding check Here.
Workaround for hba as described in the docs:
if you are running Postgres 9.5 or 9.6, and use public network access, add the firewall rule to include the public IP address of the client from where you will run the logical replication. The firewall rule name must include _replrule. For example, test_replrule. To create a new firewall rule on the server, run the az postgres server firewall-rule create command.
Please let us know if this information helps
Regards
Geetha