RCS in Samsung messages is carrier dependent, with samsung messages slowly being discontinued, carriers are pulling the RCS functionality from the app. Samsung messages is still functional without RCS. If you wish to have the RCS option, you will have to use the google messages app.
Mobile carriers are choosing to discontinue RCS support through their servers, preferring to maintain only SMS/MMS as a backup option. This decision reduces their operational costs by eliminating server maintenance. Furthermore, it may encourage users to subscribe to higher-tier data plans, as Google Messages relies on data or Wi-Fi connectivity, utilizing Google's servers rather than the carriers.
