Is it permissible to attend the gatherings of a Sufi shaykh, with caution against deviations, if he teaches correct matters in Fiqh (Islamic jurisprudence) and Hadith, and the majority of scholars in my country are Sufis?

The first [priority] for a Muslim is to safeguard their religion and creed. They should not acquire religious knowledge except from someone whose religion and creed they trust and who is free from innovations (bid'ah). If this is not possible, and they have fortified themselves and learned the correct creed, then they may acquire knowledge from someone who has no involvement with their (the innovators') creed or innovations, such as fiqh (jurisprudence) and instrumental sciences, while being cautious of any poisons they might subtly inject.