In the cults books, we read of Orlanth, Yelmalio, Yelm, Ernalda, and so on. For convenience, I use the name popularized in the God Learner monomyth – but we know that these gods have different names in different languages.
In the 1990s, Greg wrote a bunch of stories written from an in-setting perspective that often used the local names used by a given culture at a given time. Rebellus Terminus, Umatum, Elmal, Antirius, Kargzant, Yu-Kargzant, Brightface, etc. So how do worshipers navigate these names?
There are well-established techniques by which a heroquester can learn that a god will accept worship under other names, titles, and masks, and thereby establishing unity of identity. These techniques were initially developed by the Theyalans of Dragon Pass, but then greatly refined and expanded under the God Learners, and are known by many in the Third Age (although they are used with much more restraint than by the God Learners). Noted Third Age practitioners of this included Belintar, Hon-Eel, and Monrogh.
Remember, the God Learners were condemned by their contemporaries for crimes far more serious than mutilating everyone’s favorite stories to fit an understandable narrative. They were condemned for what they DID with their knowledge, and rarely for their knowledge itself.