I just don't know how to properly rip DRM protected content. Wish I did, but it's quite the confusing process.
You can get a free trial of any online streaming service that has FX or any of the channels that run open matte movies and screen record so at least you have a low res copy, better than nothing.
Use an email forwarder like AnonAddy or SimpleLogin on a VPN like ProtonVPN using Firefox so you can screen record and a privacy[.]com virtual gift card so you can't be accidentally charged and can use a fake name.
Crap. So much for the foreign releases like the French Steelbook which claimed the IMAX aspect ratio would be included.
I don't know if you have seen this already, but Zack Snyder posted this 1.43:1 scene from BvS a few days ago. https://vero.co/zacksnyder/BQ9-rJG6z188bCR2KhDJShNJ
Gotcha, I thought you were talking about a set of Regal theaters but now I understand what you are looking for. It would be nice to have the ability to understand which theater specifically you are going to so you can make an informed decision on purchasing a ticket. The size of the screen and the layout of the theater really does have an effect on the experience you will get and I will take that into consideration depending on the movie.
Here is the link to the Google Measure AR app along with an article on how it works. I'm not sure what the apple equivalent as I think it might be built in?