In the English language, the term "being with Christ on the cross" can mean being "on the cross with Christ" (like the nails were), or it can also mean being "at the location where Christ is on the cross". Both of those meanings are correct and valid usages in the English language, and most English-speaking people will have no problem knowing exactly what you mean when you use that kind of terminiology, based on the reference it is addressing.
That is why I showed you that painting and the title of that painting Christ on the Cross with Saints Mary, John the Evangelist and Catherine of Siena, to show you that that does not mean that those saints were hanging up on the cross with Christ, but they were depicted as being with Christ while He hung on that cross. As the title of that painting clearly shows, that is a correct understanding of that terminology, whether you personally understand that or not.