Welcome infantvin,
Creative Labs has never made any drivers for any of their products for Linux. The firmware and driver you were using with the X-Fi was created by a member of the community ‘Connor McAdams’. He has stated that he has no interest in building new firmware or drivers. I have this exact card. Hardware wise, it is a nice sound card.
Phoronix website claim it would be added to the 5.10 kernel, but seems to only work for the AE-5 and below.
I use my onboard built-in audio Realtek device when in Fedora Silverblue.
Until someone builds the firmware and drivers, this card will not work. Even on Ubuntu it will work in stereo mode, but as soon as you touch any sound settings it stops working.
Pipewire and Wireplumer are the packages you were probably referring to, but it can’t do anything without the drivers needed for it to function properly. I tried the flatpak package Helvum, dragging the connections around, but it still didn’t have any output.