I am confused as confused can be lol
So the Next Gen Simulations EMB11 has a place for a weather radar but it does not work?
The new bird from Caraendo has one and it works!
The CRJ one does not work, or does not for me?
The PMS 530GNS mod has one and it works?
The TBM and CRJ have them also?
I know there are some differences and all, but why is it so varied?
My question is, I guess is why is it on the payware especially is the WX Radar not working?
Weather radar does not technically work correctly in any aircraft. What you are seeing are cloud depictions and not precipitation intensity which is what a real weather radar displays. In other words, even if a plane shows weather currently it’s quite useless information.
Unless all you are interested in is seeing where the CLOUDS are on a GPS Map …
Maybe one day MSFS will have ability to show Weather Precipitation on a Display, but so far that has eluded all previous version of MSFS.
The radar in MSFS isn’t realistic.
The clouds in MSFS isn’t deadly (causing game-over).
So I don’t use the radar, another nice-to-have.
Frankly, MSFS is in a slightly different parallel universe, where icing happens every time it’s cold and you fly through moisture. This being the case, cloud radar is probably more useful than precipitation radar. 
That is why i have been using the GTN750 mod. The weather radar gives a good representation of potential icing issues. Not necessarily realistic but definitely useful.
GTN750 NexRad weather radar Limitations -
https://www.manualslib.com/manual/442986/Garmin-Gtn-750.html?page=257