We are Saved by Grace,
and Kept by Works.
Salvation history doesn't lend itself to slogans very well. The Church takes much greater pains to explain deep theology in such bodies of work as the Summa Theologica, Papal Encyclicals, the homilies and writings of the Doctors of the Church, et al, than can adequately be explained through trite jargon. When you try, you set up straw men arguments that are nothing but nonsense... they make you feel superior to your target but truly say nothing about the subject.
If you want to attack Church theology, I recommend you read an actual body of work rather than tracts about bodies of work you've never read.
Ha ha HA!!
Sola Script... ring a bell?
How about all of your endless HAIL Marys???
In reality, I find RCs are typically rather ignorant of what their church teaches, and the degree of interpretation such are is subject to, and what magisterial level it belongs to, as seen by her sects, esp. with the apparent contradictions among the plethora of prolix publications by prelates.
RCs also have a great deal of liberty to interpret Scripture in ways to support Rome, while censuring us for engaging in "private interpretation, which they wrongly interpret 2Pt. 1:20 as condemning!
Yet the weight of Scriptural substantiation is not the basis for RC assurance of Truth, but which based upon the novel premise of perpetual ensured magisterial infallibility.