E-MU 0404 USB 96 kHz Recording

I'm trying to use a E-MU 0404 USB soundcard for sound recording on 
Debian 11 with jack and ardour. It works well if I use a 48 kHz sampling 
rate, but if I go up to 96 kHz I get severe sound distortions. A post in 
this forum discussion (post #25):

https://www.diyaudio.com/forums/equipment-and-tools/338888-mu-0404-linux-issues-rew-96-khz-3.html?s=4e4a688f32b10c56f39c3d4ed6133091

suggests that the problem can be circumvented by using the card as a 
2-channel device (disabling the SPDIF inputs, which I don't use anyway), 
and gives an example of the `.asoundrc` configuration needed to achieve 
that. I tried that solution by putting this in my `.asoundrc`:

pcm.emu2ch {
   type hw
   card "USB"
   device 4
   format S24_3LE
   channels 2
}

ctl.emu2ch {
         type hw;
         card 4;
}


but I'm unable to initialize jack from the command line calling the 
`emu2ch` device. I get the following error:

creating alsa driver ... 
emu2ch|emu2ch|1024|2|48000|0|0|nomon|swmeter|-|32bit
ALSA: Cannot open PCM device alsa_pcm for playback. Falling back to 
capture-only mode
cannot load driver module alsa
no message buffer overruns


In qjackctl I don't see the 2-channel version of the card as a 
selectable option.

My understanding of options for calling jack from the command line is 
quite limited. My understanding of `.asoundrc` configuration options is 
even more limited. I'm hoping that someone could point me out to a 
solution to use the card as a 2-channel device through jack, and thus 
hopefully circumvent the sound distortion issue when recording at a 96 
kHz sampling rate.

Best,

Sam