dinga

I had the same problem with a west-facing bedroom. Have both the window film (easy to install DIY) and curtains with the silver fabric backing (both were professionally made-to-order, with the silver fabric attached to the curtain with velcro - which also reduces fading and extends the life of the curtains). Problem solved so long as the curtains are closed, and the windows left open - I've found the film alone to be insufficient.

Sorry - ALMOST identical but NOT identical it seems https://www.sciencefocus.com/the-human-body/do-identical-twins-have-identical-genes/