Just buy a few of these for that specific purpose! ;-)
https://www.amazon.com/gp/product/B01M31NA6E/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
In fact, I actually just took the similar strips from my old Thule crossbar that had a similar gear grove along the rail. Then because of the...
Make sure you have “always on” in the location settings for the Rivian app and not “just while using app”.
Also, it can be even more laggy if you turn on iPhone “battery saver mode.”
PAAK Primary (has been working well) with key card in wallet as backup (same for my wife). Fob in kitchen drawer... just another thing to carry around.