There is one body of Christ that He is building and it is comprised of born again believers.
Denominational affiliation is irrelevant between Christ followers.
If it isn't irrelevant, they are not focused on the right thing, that is Christ.
Catholics love to point out what they consider disunity amongst Protestants as if denominations are significant. They're not. Not any more than the variety found in the seven churches in Revelation 2 & 3. Each one of those was different from the other, as evidenced by what Christ spoke to them individually about. And yet they were all churches that Christ recognized as His own.
Sometimes there are different denominations based on geographic location, sometimes focus on ministry.
It's not a big deal except to those who would like to use it to disparage others and build themselves up.
Hebrews 12:1-2 Therefore, since we are surrounded by so great a cloud of witnesses, let us also lay aside every weight, and sin which clings so closely, and let us run with endurance the race that is set before us, looking to Jesus, the founder and perfecter of our faith, who for the joy that was set before him endured the cross, despising the shame, and is seated at the right hand of the throne of God.
1 Corinthians 12:12-27 For just as the body is one and has many members, and all the members of the body, though many, are one body, so it is with Christ. For in one Spirit we were all baptized into one body—Jews or Greeks, slaves or free—and all were made to drink of one Spirit.
For the body does not consist of one member but of many. If the foot should say, “Because I am not a hand, I do not belong to the body,” that would not make it any less a part of the body. And if the ear should say, “Because I am not an eye, I do not belong to the body,” that would not make it any less a part of the body. If the whole body were an eye, where would be the sense of hearing? If the whole body were an ear, where would be the sense of smell? But as it is, God arranged the members in the body, each one of them, as he chose. 19 If all were a single member, where would the body be? As it is, there are many parts, yet one body.
The eye cannot say to the hand, “I have no need of you,” nor again the head to the feet, “I have no need of you.” On the contrary, the parts of the body that seem to be weaker are indispensable, and on those parts of the body that we think less honorable we bestow the greater honor, and our unpresentable parts are treated with greater modesty, which our more presentable parts do not require. But God has so composed the body, giving greater honor to the part that lacked it, that there may be no division in the body, but that the members may have the same care for one another. If one member suffers, all suffer together; if one member is honored, all rejoice together.
Now you are the body of Christ and individually members of it.
“Not any more than the variety found in the seven churches in Revelation 2 & 3. Each one of those was different from the other, as evidenced by what Christ spoke to them individually about. And yet they were all churches that Christ recognized as His own.”
Also, according to Catholic belief, they claim those churches as their own, since this is pre-Reformation, and they do not hold to the dispensational interpretaion of that section. Yet, already, in the first century, Christ himself notes the differences in teachings and beliefs between those churches. So much for universality!