It's hard to say, but personally I think it will be fine if you're only dealing 1 enemy. Afaik both sets of 5th bonus are only affect 1 enemy. Let's assume you can proc them non-stop in the whole fight.

Way of fire will provide 2k dps and shadow of red mountain will be 4.2k dps, that'll be 6.2k dps (should be higher if you have invest more cp and apply some major/minor buffs I think) from these 2 sets, the rest of your dps will heavily rely on 2nd, 3rd and 4th set bonus (and monster set, weapon + jewelry + armor enchantment ofc) It will probably not that worth it if you're fighting against a bunch of adds or some boss fights that will spawn adds.

I think the question would be "how much dps do you think it's bad". Like if your standard is 30k dps, then you have to make up 23.8k dps from the rest of set bonus.

But that's just my opinion, I never try this combo before, so it might be really good probably.

p.s.: just noticed way of fire is heavy armor set, so probably need to transmute jewelry (150 transmute crystals cost)

Look for xynode, he is a YouTube eso content creator and has an extensive site, try his Murder of Fire build, just make sure you watch the hour video that goes with it for lots of tips and tricks, I think that will be right up your alley

Used it myself, once you understand how it works it’s like having your own personal pyrotechnics department, also it’s easy to adapt it to make it your own