I feel you!
Besides the Sneak Ruleset, I think ti is actually quite hard to consistently win with Fire. I sometimes see it work with Plado Emberstorm, but don't want to spend another 70$ right now, just for that.
I guess like you said, investing in neutral monsters could be a better choice.
Thank you ;)
And yeah, the prismatic energy is nice. I usually use the double magic reflect in the Armored Up Ruleset, works quite well there. I believe that it is a good combo in general, but a healer is needed!