That is what I believe too. Another person commenting said that these 144,000 will help Jesus govern for 1000 years, and they may. However, in Rev 7, it clearly shows that they are on Earth with God’s seal and that they delivered many people.
It’s a simple reading of the passages....the sealed 144000 appear then boom uncounted multitudes are saved from the beast system....yes the 144000 have a special song that no one knows but God and them them...but hey..God does what God does!