I'm afraid this is not indicative of the request at all. In fact, passing it through a few eyes confirms that it just looks either grammatically incorrect or misleading.
-> "I need to find a mission that has nothing but lvl 30 enemies? Where's that?"
A solution would be being clear and straight to the point. "Starting at level 30" should be sufficient even for those that do not have high English proficiency.
However, the issue with this challenge does not end there. It doesn't seem to acknowledge the infested faction, or at least seems to be completing sporadically for clients alone - as shown in the threads of the Bug Reports section of the Forums, as well as the state of complaints chat in the recent nightwave missions have caused.
Now this is a strange decision - the main source of complaints would be regarding audio indicators and colour coding, which have been deemed a bad design choice for decades now due to being difficult to register even for those without physical issues, in abundance of audio and visual content the game is throwing at them on a regular basis, and fully disregard the existence of players with particular needs in terms of perception. Leaving the enemy marker as the sole point of realization where the enemy is leaves still demands a lot of running in various directions in absence of other cues, but it left time for people to search for it on the map. Once found, they would have sufficient time to deal with it before it reaches its objective of destruction. Lowering the distance at which the enemy marker appears leaves less time to deal with the demolysts and will inevitably leave those without beefy equipment or knowledge on game dynamics at a loss.
Increasing the distance at which the enemy marker spawns would be a solution, further than it originally was. Abandoning colour coding and audio indicators as a sole hint method would as well. Adding shapes to tower markers was a good step forward, although colourblind players still complain it's difficult to distinguish in a mess of enemies and trying to stay alive. Dismissing the polygonal frame around the shapes could solve this, or perhaps reshaping the entire marker into its respective shape. Perhaps somewhere in the future, the colour choices could be made accordingly to existing user-friendly design standards which would include those that cannot see certain tints against certain backgrounds.