All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad is His slave and Messenger.
The view that the congregational prayer is a condition for the validity of the prayer is the view of Ibn Hazm and some scholars of the Hanbali School of Fiqh. However, this view is different from the view of the majority of the scholars and different from the adopted view of the Hanbali School.
In any case, we have not come across any statement of the scholars - who condition the congregational prayer for the validity of the prayer - that says that a person who deliberately prays by himself is a disbeliever.
Allaah knows best.