A very strange out-of-nowhere fix, with suspend now working as desired:
fresh install of fedora 37, 6.10 kernel, same hardware, xorg. Both screens are working with this as well! (I find 1400x900 on the laptop monitor next to my 1080p main display looks quite nice)
nvidia drivers and egpu-switcher installed (interestingly: it says my graphics card is an MSI external audio device during egpu-switcher setup now, as opposed to a GTX1650S like it used to in older versions of the program)
the NVreg temp directory module parameter set and new initramfs generated with dracut
Before the fix, suspending would immediately wake
disabling TDM1 in /proc/acpi/wakeup will allow me to suspend with software trigger or the laptop power button. Wake is also possible with power button or keyboard.
Hopefully this helps someone! if TDM1 doesn’t work, sudo sh -c "echo devicename > /proc/acpi/wakeup" for all enabled devices in your wakeup file, test suspend after each one until you find the right one (heads up, PWRB is the power button, don’t disable that one).