You are 100% correct.
We owe all to the grace of God and not by our rightousness.
The Bible made it clear that our rightousness is like filthy rag befor God.
Isaiah 64 vs 6
But we are all as an unclean thing, and all our righteousnesses are as filthy rags; and we all do fade as a leaf; and our iniquities, like the wind, have taken us away.
It's only by his grace we are saved.
Good addition - thank you