Great questions. From what I've read it's true that a smart meter cover alone may not provide adequate protection. For some meters, the grounded metal from the smart meter box blocks the majority of radiation from getting into the home but this is not guaranteed.
To find out, get an EMF meter and measure the RF spikes. Remember, measure the spikes because RF is sent in packets, and is not transmitted all the time. Note I've also heard that many smart meters are actually specifically designed to look like analog meters, with a mechanical spinning wheel, but are in fact transmitting data wirelessly. The only way to know if it's truly analog is to get an EMF meter. If you are seeing large spikes in radio frequency on your EMF meter at distinct intervals, you have a Smart Meter installed.
You can make your own smart meter cover:
-wrap tinfoil around the side of the meter to direct the signal out the front (this will eliminate the majority of the radiation and stop it from traveling sideways into your house)
-shield the front of the meter: wrap aluminum screening over the top
-hose clamp it in place
Take measurements before and after to be sure you did a proper job of protecting your home.
If you take measurements an the radiation is getting into your home from the back of the meter, there is EMF protection paint you can buy to paint that wall (it's extremely expensive). Alternatively, what I plan on doing is buy an EMF blocking picture frame liner. So you hang a piece of artwork on the wall opposite your meter. the frame of the artwork has the EMF blocking liner in it.
https://www.shieldyourbody.com/product/emf-poster-frame-liner/?billing_country=USPlease note: this is just my idea. I haven't tried it yet so can't vouch for it's shielding effectiveness. I share it in case it helps somebody else. The more solutions we share the better. If anyone tries this, please post here and tell us how it went.