Of course GSX Pro is a 64 bit application: by default is installed in Program Files (x86), but there's a "couatl" folder (32 bit version for FSX and P3D up to V3) and a "couatl64" folder inside where the 64 bit versions are found.
The "Program Files (x86)" location is just a name: a program doesn't become 32 bit or 64 bit "just" because it's installed there. A a 32 bit program would not be "promoted" to 64 bit "just" because it was installed into "Program Files" and surely a 64 bit program won't be "downgraded" to 32 bits just because it's in "Program Files (x86)". A program is 32 or 64 bit depending how is compiled.
That is without saying the "Program Files (x86)" is just a suggested DEFAULT folder during the installation, but you can change it to install into any folder or drive, that won't clearly change how the programs is.
So, to recap:
- If you use FSX or P3D up to version 3, those are 32 bit simulators, so the 32 bit version of Couatl engine will run GSX.
- If you use P3D4, 5 or 6, which are the 64 bit versions of P3D, a native 64 bit version for P3D 64 bit will start instead.
- If you use MSFS 2020, a native 64 bit version for MSFS 2020 will start.
- If you use MSFS 2024, a native 64 bit version for MSFS 2024 will start.
