>>38347016Solgaleo is based on the Lion that Devours the Sun, the symbol of the purification of metal in alchemy. Solgaleo isn't a personification of the sun, it's an emissary of it (this is outright said in the games): something that is subservient to it, draws power from it, but it isn't the sun.
So basically, Solgaleo is an emissary of the sun that embodies the concept of purification and is based on the Lion that Devours the Sun from alchemy, who was the symbol of the purification of metals (hence the Steel/Psychic type).
To me it makes sense that it's weak to fire, it's not actually the sun it just draws power from it. It probably should have had flash fire as an ability.
So, does that make sense?