Can’t you just disable RCS in the Google Messages app and use a different messenger? You can just change the default SMS app to one that doesn’t do RCS (which is almost all of them).
Edit:
I can rely on SMS even when there is no data signal, can’t say that for RCS.
Users in many cases switch cellular data usage off locally on their device. To allow the MNO
to offer IR 92 / IR 94 and RCS services to their users even in these use cases, the data off
switch shall have an MNO configurable impact on the device connectivity. It shall be up to
the individual MNO to ensure a good Operator service experience by the end user in cases
that allow IP service usage even if the data switch was set to ’off’ by the end user.
“MNO” refers to the cellular network operator you have a subscription with.
Of course, this requirement cannot be satisfied if you use a random internet server (such as Google’s) for RCS, rather than your carrier’s. This is a problem with Google’s servers, RCS itself was designed to operate even if you have data disabled. 4G and later are completely packet-based, so there is no “no data signal” situation, just “terrible reception and slow data rates”.
Can’t you just disable RCS in the Google Messages app and use a different messenger? You can just change the default SMS app to one that doesn’t do RCS (which is almost all of them).
Edit:
The RCS Universal Profile Service Definition Document has the following to say about that:
“MNO” refers to the cellular network operator you have a subscription with.
Of course, this requirement cannot be satisfied if you use a random internet server (such as Google’s) for RCS, rather than your carrier’s. This is a problem with Google’s servers, RCS itself was designed to operate even if you have data disabled. 4G and later are completely packet-based, so there is no “no data signal” situation, just “terrible reception and slow data rates”.