Is it permissible to belong to the Ansar al-Sunnah al-Muhammadiyah group in Sudan, taking into account its methodology based on the Sunnah and the Book, and is this considered a division among Muslims, and is it permissible to pray in Sufi mosques?

The Jama'at Ansar al-Sunnah is one of the Salafi groups that revolve around the Qur'an and Sunnah. There is no harm for a Muslim to join it, provided there is no fanaticism or partisanship, while accepting the truth from whoever brings it, and engaging in mutual advice and cooperation with all Muslims.