I found another workaround that worked for me in LUKS password prompt hidden after installing Nvidia drivers without the need to do anything else.
My motherboard has an integrated Intel GPU and I use a PCIe NVIDIA card. By disabling the “Intel Processor Graphics” in my BIOS, I was graphically prompted to input my LUKS passphrase. Prior to disabling, I got a blank screen like @itsmemo and many people have reported when using the proprietary driver with an encrypted filesystem.
While the GPU alone meets all of my needs, this won’t help users that need to use both the integrated graphics and the GPU.
This doesn’t address the root issue but might hint having multiple graphics (integrated and dedicated) available when booting could cause some confusion or conflict in the kernel and/or driver.
Unimportant background to my journey
I decided to try Fedora 41 Workstation on a ~10 year old desktop.
Media creation took a few attempts since Windows 10 kept touching something.
GDM kept crashing whenever I resized a window (or did a few other things) causing me to re-login. This happened both when running live from USB and from disk after install.
The nouveau driver booted and permitted graphically entering the LUKS passphrase just fine (even with the integrated graphics enabled in my BIOS) but I need to be able to resize windows and the generally advocated, easier solution was to give up and use the proprietary driver.