Orphee after reading this linked in the article, which states
B. Google Play Services Telemetry
The Google Message and Dialer apps do not send data directly
to Google, but rather send data to event logging services
within Google Play Services. Specifically, to the Clearcut
logger service and the Google/Firebase Analytics service.
These Google Play Service components expose APIs that the
app uses to communicate with them. The Clearcut logger and
Google/Firebase Analytics services then batch up data received
and forward it to Google servers. The Clearcut logger sends
data to https://play.googleapis.com/log/batch while Google/-
Firebase Analytics sends data to https://app-measurement.
com/. This process is illustrated schematically in Figure 5.
The Clearcut logger and Google/Firebase Analytics services
encode the data in different formats for sending to Google.
It may be possible to revoke network access/background data of Google Play Services/GSF if not used elsewhere, and that should disable the telemetry from Google Messages. I will look into this as I am also looking for a text messaging application.