@jonathandavid: Check out this post:
Here is one of the key paragraphs from that guide:
Because Google has consolidated the RCS messaging infrastructure, it creates a problem for dumbphone support. The only way to use the Google Jibe RCS server is with Google’s proprietary Google Messages app. And the only way for dumbphone companies to add the app to their devices is via an agreement with Google to support Google Play Services. [emphasis added] This is often a non-starter either due to the stripped down version of Android many dumbphones run and/or it goes completely against the mission of many dumbphone companies to support fewer apps to eliminate distractions.
For privacy reasons, Mudita specifically does not use any Google software in its AOSP-based MuditaOS K. Similarly, and for the same sake of privacy, the maker of iodéOS – also AOSP-based – does not use any Google software.