Well, despite the fancy language, malachite green & formeldahyde ("aldahydes" are in this category) is pretty much the "old school" treatment. I'm not sure what "protective polymers" are (sounds almost like plastic coating, doesn't it, lol). To this old-timer, it sounds better than the salt, nitrofurazone & dye you're using (too many ingredients but maybe not enough of any? I don't know if they tell).
I forget after all this long thread what day of treatment you're on... You're getting so close!!! Are the corys still ok? Don't stop tx too soon, you know that.
The heater, well, it "used to be said" that high heat ~92F would kill ich but there is definitely a heat resistant form these days. Higher heat does speed the ich lifecycle & your rams might be ok with that but not your corys, other fish or plants. I would not suggest you do that!
Since you're "almost" done, can you get that med or something similar locally? Yep, you have to read ingredients, but it may be as good as ordering online plus shipping fees &/or time...If you lfs is open & you feel safe to go there. It would be worth a phone call anyway...with a quick search to see if they have something close... (Victoria green is very similar to malachite green)
I'm happy your rams are feeling good!