Complex sentence: In that season, the Galicians went on to conquer their first league title, with the player subsequently returning to "Depor", where he appeared very rarely in his last season, which ended in Copa del Rey conquest.
Split into simpler sentences: In that season, the Galicians went on to conquer their first league title, with the player failing to contribute in that competition. Subsequently, he returned to "Depor", appearing very rarely in his last season, which ended in Copa del Rey conquest.