I agree with you that by trying to be good we are not doing much. We must love each other with all our hearts and before that love our God. By letting the Holy Spirit in our hearts.
Being good is an outcome.
I agree we cannot judge Saint Teresa which path she took. I strongly believe her goodness was an outcome of her simple and uncorrupted soul and closeness to God.
Here is one anecdote.
A journalist after seing the poor and dying in the home of Mother Teresa said to her, “I wouldn’t be doing what you’re doing, not for a million dollars.”
“I wouldn’t either.”, replied Mother Teresa.