Thanks for sharing your experience.
My research of the transit visa led me to believe that, despite the contrary information from the official Saudi website, it’s currently only setup and available if you are flying on their National airlines. I eventually desisted with the transit visa option and applied for the E-visa.
I’m really curious how the immigration setup is at RUH. There is info out there that Terminals 1-4 are now connected and implied that they within the secure area. But I haven’t been able to track anyone to confirm this. But the big question is where you exit after immigration? If you have an option of exiting into the secure area in Terminals 1-4 or if everybody, because of the lack of connecting airlines at these terminals, gets routed to 1 common area outside of security.