Highly recommend that Sproul article I sent. I think it would help clarify some of the issues.
Long story short, the rift between Rome and the Reformed is significant and irreparable unless Trent is completely repealed. You could look into the differences between _monergistic_ and _synergistic_ regeneration, you could look into the differences between sacerdotalism and the 'priesthood of all believers,' you could look at what the Reformed have to say about an _ex opere operato_ nature of the sacraments, transubstantiation, the 'immaculate conception' and role of Mary as co-mediatrix and therefore co-redemptrix, you could look at what the RCC means by the mass being a "re-presentation" of the "victim"...the list goes on and on, sadly.
The key place to start would probably be the debate over the '[Five Solas](https://reformationbiblecollege.org/blog/the-five-solas)'. Also helpful may be a review of the controversial "Evangelicals and Catholics Together" movement of the mid-nineties where a rapprochement was attempted, but failed: see Horton, "[ECT - A Critical Review](https://www.modernreformation.org/resources/articles/evangelicals-and-catholics-together-a-critical-review)"
On these points, Rome and the Reformed are irreconcilable.
All that said...sigh...we can confess, uphold, and defend the Apostles' and the Nicene Creeds in common. And that, at least, is a starting point. Appreciate the dialogue, my friend. 🤙
