What kind of sound system are you using? Is this solely an issue with Netflix?
For what it's worth, in my opinion most TV speakers are designed to be awful because they either point the audio down or backwards and the sound is guaranteed to sound more muddled than the original signal because it's bounced around before it gets to you.
You need forward facing speakers (preferably with a dedicated center audio channel as in a 5 speaker surround sound setup) to get the maximum benefit.
I have noticed that Netflix tends to default the audio to 5.1 even when I'm watching on a TV that only has stereo speakers attached and switching back to stereo significantly improves the dialogue situation.
I had this problem with Netflix and basically every other streaming service until I bought a sound bar. I think I paid $100 for it and suddenly all the dialogue was clear
Get an audio receiver with midnight mode which compresses the audio. I haven’t noticed Netflix being worse than others on this.
Have you directly compared one and the same movie on Netflix and another medium (DVD/Blu-Ray/another streaming service)? Maybe your problem isn't with Netflix.
Movies generally tend to have a high dynamic range. That's how they play in the cinema where action scenes are supposed to stand out from the dialogue and that's how many people want them in their home theatres as well.
I personally did not notice anything special with the audio on Netflix.