Greetings!
If you are using a private link to connect to your Azure database, the decommissioning of gateways by Microsoft will not impact your connectivity. The IP address will remain unchanged when using a private endpoint.
However, if you are using a public IP address, it is recommended to use the Fully Qualified Domain Name (FQDN) in your connection strings, as the IP address associated with the public endpoint may change. This ensures that your connections remain consistent even if there are underlying changes to the public IP addresses.
Private Link for Azure Database for MariaDB
Connect to Azure Database for MariaDB
Fully Qualified Domain Name (FQDN) in Azure
Regards
Geetha