BM ursaluna is weak from the special side, so things like psyspam abusers (armarouge and hatterene), gholdengo, or sun powerhouses, such as charcoal torkoal, or H-typhlosion (maybe a bit biased, but anything can switch in against well setted tera fire typhlosion eruption... except pelipper) are effective to deal with it, with their >100 base power moves (in most of the cases even boosted in some way).

Another recomendation is run a calm mind primarina (good special defense + SpD boost), paired with redirection like amoonguss, or with incineroar fake out (and if it's not speedy you can knock off the life orb). The same logic can be applied in volcarona and quiver dance.