There are “big tent” and “pup tent” ways to formulate doctrine. I like this one: Faith alone saves, but the faith that saves is not alone.
Not without compromising the gospel there isn’t. Even in your attempt you left out vital elements—Grace and Christ. Any addition to grace, faith, or Christ nullifies the gospel. Read the apostle Paul. He said in Galatians that those who attempted to add even one thing—circumcision—should be damned to Hell. It was that essential.
The truth is there will be many who claim to be Evangelical or Protestant who will join your call for unity, but there will always be a remnant who simply can’t.