GSMA added end to end encryption using MLS to the RCS universal profile in March. For one to one messages the latest betas of Google Messages contain a flag to

GSMA added end to end encryption using MLS to the RCS universal profile in March. For one to one messages the latest betas of Google Messages contain a flag to enable MLS support. It is expected Google will add the support for group messages and enable MLS by default sometime soon. Apple has committed to supporting MLS in a future update. So eventually there will be end to end encryption between the two ecosystems.