This may not be something that bothers anyone else or you already have a solution that works for you like holding it up when you go through a toll. Or a license plate mount, but being in a state that doesn't require a front plate I didn't want to go that route.
I don't like seeing the back of the EZ-Pass transponder on the windshield from the outside of the car when its in the classic hiding spot behind the rearview mirror. For me this is compounded in the Giulia because this space is already used by the built in camera and wiper sensor. I also don't like seeing it on the dash or even the reflection in causes in the windshield, hopefully other people are less OCD about this.
The best option I have found is https://mypasscover.myshopify.com
which I really like but has a couple of issues.
First their Alfa Romeo Giulia fabric option is the leather used for the premium dash, so people like me that didn't pay for that can't get an exact match.
Second the cover is designed to be exactly the same dimensions as the transponder which means if its on a sloping part of the dash the cover strap that goes under the transponder holds it off the dash and in some positions you will see a gap and the velcro holding it down. This can at least partially be addressed by swapping the velcro that comes on the transponder with the much thinner stuff supplied with the cover.
The picture is of one of the newer smaller i-Pass transponders with one of the older larger square EZ-pass covers in Alfa Romeo leather on a vinyl dash. The flash for the picture highlights the difference in texture, in daylight its less apparent. On the upside it sits behind the inspection stickers so does't obscure any view but still allows a windshield sun shade to be used when parked. The larger cover also tips the edge facing me and the gap disappears completely. There is no reflection in the windshield and the EZ-pass is invisible from outside the car. Finally most importantly there is absolutely no problem with the EZ-Pass working through the cover and the Giulia windshield. I was initially worried that there was but it turned out that the battery in my probably 10 year old transponder had run down.
This is an option to make the transponder less visible and the company has been responsive to my emails, even doing a trip to an Alfa Romeo dealer to see whether they had a better fabric match for the non leather dash.