"YOU are (((all))), in fact, sons of God through YOUR faith in Christ Jesus.” (Galatians 3:26)

There is no 'your' in the Greek.
There is "the"

Add in scripture
The faith OF Jesus Christ apportioned to us
And we will understand what Galatians says
YOU are (((all))), in fact, sons of God through THE faith OF Christ Jesus.” (Galatians 3:26)

Our faith is not even our own
You are saved by grace through faith, and this is not from yourselves but a gift of God