Well it seems the issue has been “solved” .. they just removed the humidity slider 
No, the humidity slider was removed quite a while ago.
But feel free to buy the slider back into your FS by paying RexSimulations a few bucks for Rex Atmos Core. REX Atmos CORE – Next-Gen Weather & Atmosphere Engine for MSFS 2024
The sim still models humidity. The slider just did nothing so they removed it.
So how does the sim model it if you can’t change it ? How do you get 10km visibility without clouds ?
It just does it dynamically I guess, based on the weather conditions
Use Rex Atmos Core. It is the only way to “fix” this.