No because it’s not stacking, so one effect for each elemental damage type is possible.
For example we can have lightning damage stuns enemies for x seconds “shock therapy”, then another one for fire burning effect of increasing damage over time “deep burns”. Then you can have another lightning effect called “shockwave” where enemies killed with lightning damage explodes to do aoe dmg, and another fire damage called “arson”, where enemies that are burning can spread to other enemies that make contact with them.
You can choose these effects as build “enhancers” rather than “forcers”. You can choose to have both lightning effects or one fire one lightning, and they will all be “situationally beneficial”, ENCOURAGING build diversity — similar builds may also choose different effects that compliment each other and sync up, or compound the effect. So you have even MORE variety in a particular build type.
And even if it does stack, it doesn’t require you to stack a certain amount to “unlock” an additional modifier, you can simply get a greater effect, but it’s not multiplicative, so having two different effects won’t be less than stacking two of the same.
The whole power affix to “unlock” idea is stupid, imagine when you need 40 to unlock a “power leap” but you only have 39… clumsy design.
And when I say power leap I don’t mean the name of an effect, I’m talking about the design mechanic of a leap in power suddenly, like set bonuses, this would just be another set “step” system but with only 3 options… super lame