FFMPEG doesn’t detect CUDA-capable device

I’ve built ffmpeg according to the guide:

and I am trying to start it with:

ffmpeg -y -hwaccel cuda -hwaccel_output_format cuda -i input.mkv -c:a copy -c:v h264_nvenc output.mkv

but hardware acceleration refuses to work, returning the following error:

[h264 @ 0x55f93f7c1880] NVDEC capabilities:
[h264 @ 0x55f93f7c1880] format supported: no, max_mb_count: 0
[h264 @ 0x55f93f7c1880] min_width: 0, max_width: 0
[h264 @ 0x55f93f7c1880] min_height: 0, max_height: 0
[h264 @ 0x55f93f7c1880] Hardware is lacking required capabilities
[h264 @ 0x55f93f7c1880] Failed setup for format cuda: hwaccel initialisation returned error.
[h264 @ 0x55f93f7c1880] Format cuda not usable, retrying get_format() without it.

In all other program GPU works like a charm:

Mon Dec 25 21:48:08 2023
+---------------------------------------------------------------------------------------+
| NVIDIA-SMI 545.23.08              Driver Version: 545.23.08    CUDA Version: 12.3     |
|-----------------------------------------+----------------------+----------------------+
| GPU  Name                 Persistence-M | Bus-Id        Disp.A | Volatile Uncorr. ECC |
| Fan  Temp   Perf          Pwr:Usage/Cap |         Memory-Usage | GPU-Util  Compute M. |
|                                         |                      |               MIG M. |
|=========================================+======================+======================|
|   0  NVIDIA RTX A6000               On  | 00000000:01:00.0 Off |                  Off |
| 56%   81C    P2             274W / 300W |   8584MiB / 49140MiB |     98%      Default |
|                                         |                      |                  N/A |
+-----------------------------------------+----------------------+----------------------+

+---------------------------------------------------------------------------------------+
| Processes:                                                                            |
|  GPU   GI   CI        PID   Type   Process name                            GPU Memory |
|        ID   ID                                                             Usage      |
|=======================================================================================|
|    0   N/A  N/A      6458      G   /usr/lib/xorg/Xorg                          268MiB |
|    0   N/A  N/A      6574      G   /usr/bin/gnome-shell                        165MiB |
|    0   N/A  N/A    229342      C   /home/ic/.local/vrec/ve/bin/python3        8050MiB |
+---------------------------------------------------------------------------------------+

What else could I check?
What additional infos are needed to localize the problem?

I’ve read all similar topics on the forum, and didn’t find anything what could help me.

Thanks a lot in advance