Is it permissible for Muslims to perform the rituals of Christians and Jews (before alteration) alongside the rituals of Islam, knowing that Islam supersedes what came before it?

It is not permissible to worship Allah the Almighty with acts of worship mentioned in previous laws unless Islamic Sharia approves them. The previous divine scriptures have been distorted, and Islamic Sharia supersedes them. What Islamic Sharia has affirmed is true, and anything else is either abrogated or false. There are three categories for what was present in previous laws: what Islam has affirmed and we worship with it, what Islam has abrogated and it is forbidden to worship with it, and what was never originally legislated but is an innovation and false. It is not permissible to combine the Christian creed based on the Trinity with the Islamic creed based on monotheism.