I know, I know, Ali Express is not a very good site, but it made me think it could be used to give the L5 a better Cell Tower connection stability, since I read some posts about the issue here.
Product’s name is 10Pcs Outdoor Cell Phone Signal Enhancement Stickers Mobile Antenna Amplifier SP-11Pro Enhance Boosters Camping Tools
I wont include the URL since its lenghty, and to my testing, some countries get an error message for trying to visit the specific product. So, if you are interested you can simply copy paste the bolded text into the searchbar of its website.
As said this is just an idea