You mentioned data. I believe that many indigenous people overestimate their ability to speak a language. It is perhaps the same for francophones, or those who have learned French as a second language outside Quebec. They say they are bilingual, but, in reality, their language level is a little weaker than they think.
Is it the same for indigenous languages? You are an expert in linguistics. Are the data we have today sufficient to allow us to act, or do we really need an in-depth study to understand the current status of indigenous languages?