I have the full (paid) Ring Protect Plus subscription, I am located in Luxembourg, and I cannot get the discount, neither on the Ring site (which for Luxembourg redirects to the French shop, might be part of the issue), nor via my linked Amazon account.
There are already a bunch of questions about this (Sorry cannot link because new account)
From the description of the plan it is pretty clear that the discount should work for regular Ring devices (i.e., the ones that are listed on the US shop in this section NB: you need to set your location to US for the page to work), but it looks like this has not been setup for non-US shops. (e.g., if you switch the country to UK or FR, that shop page does not exist)
Could someone from Ring please fix this?