Amazon RDS now supports T4g instances for MySQL, MariaDB, and PostgreSQL databases.

Amazon Relational Database Service (Amazon RDS) now supports AWS Graviton2-based T4g database (DB) instances for MySQL, MariaDB, and PostgreSQL  databases. T4g DB instances offer up to 36% better price performance over comparable current generation x86-based T3 DB instances depending on the workload characteristics.

Source:: Amazon AWS