Samsung signed a deal so that they can use the Jibe API to be a part of E2E when using RCS.
Since I'm sure there's Internet where you're at, you can take a look from Verizon's RCS roll out on messages+ in 2021 to Samsung's S9, prior to relying on Google Jibe. Verizon did eventually switch to use Jibe for their entire RCS implementation now instead of relying on their own infrastructure as did T-Mobile.