Why are torch.version.cuda and deviceQuery reporting different versions?

I have a doubt about the CUDA version installed on my system and being effectively used by my software.
I have done some research online but could not find a solution to my doubt.
The issue which helped me a bit in my understanding and is the most related to what I will ask below is this one.

Description of the problem:

I created a virtualenvironment with virtualenvironmentwrapper and then I installed pytorch in it.

After some time I realized I did not have CUDA installed on my system.

You can find it out by doing:
nvcc –V

If nothing is returned it means that you did not install CUDA (as far as I understood).

Therefore, I followed the instructions here

And I installed CUDA with this official link.

Then, I installed the nvidia-development-kit simply with

sudo apt install nvidia-cuda-toolkit

Now, if in my virtualenvironment I do:

nvcc -V

I get:

nvcc: NVIDIA (R) Cuda compiler driver
Copyright (c) 2005-2019 NVIDIA Corporation
Built on Sun_Jul_28_19:07:16_PDT_2019
Cuda compilation tools, release 10.1, V10.1.243

However, if (always in the virtualenvironment) I do:

python -c "import torch; print(torch.version.cuda)"

I get:

10.2

This is the first thing I don’t understand. Which version of CUDA am I using in my virtualenvironment?

Then, if I run the sample deviceQuery (from the cuda-samples folder – the samples can be installed by following this link) I get:

./deviceQuery 
./deviceQuery Starting...

 CUDA Device Query (Runtime API) version (CUDART static linking)

Detected 1 CUDA Capable device(s)

Device 0: "NVIDIA GeForce RTX 2080 Super with Max-Q Design"
  CUDA Driver Version / Runtime Version          11.4 / 11.4
  CUDA Capability Major/Minor version number:    7.5
  Total amount of global memory:                 7974 MBytes (8361279488 bytes)
  (048) Multiprocessors, (064) CUDA Cores/MP:    3072 CUDA Cores
  GPU Max Clock rate:                            1080 MHz (1.08 GHz)
  Memory Clock rate:                             5501 Mhz
  Memory Bus Width:                              256-bit
  L2 Cache Size:                                 4194304 bytes
  Maximum Texture Dimension Size (x,y,z)         1D=(131072), 2D=(131072, 65536), 3D=(16384, 16384, 16384)
  Maximum Layered 1D Texture Size, (num) layers  1D=(32768), 2048 layers
  Maximum Layered 2D Texture Size, (num) layers  2D=(32768, 32768), 2048 layers
  Total amount of constant memory:               65536 bytes
  Total amount of shared memory per block:       49152 bytes
  Total shared memory per multiprocessor:        65536 bytes
  Total number of registers available per block: 65536
  Warp size:                                     32
  Maximum number of threads per multiprocessor:  1024
  Maximum number of threads per block:           1024
  Max dimension size of a thread block (x,y,z): (1024, 1024, 64)
  Max dimension size of a grid size    (x,y,z): (2147483647, 65535, 65535)
  Maximum memory pitch:                          2147483647 bytes
  Texture alignment:                             512 bytes
  Concurrent copy and kernel execution:          Yes with 3 copy engine(s)
  Run time limit on kernels:                     Yes
  Integrated GPU sharing Host Memory:            No
  Support host page-locked memory mapping:       Yes
  Alignment requirement for Surfaces:            Yes
  Device has ECC support:                        Disabled
  Device supports Unified Addressing (UVA):      Yes
  Device supports Managed Memory:                Yes
  Device supports Compute Preemption:            Yes
  Supports Cooperative Kernel Launch:            Yes
  Supports MultiDevice Co-op Kernel Launch:      Yes
  Device PCI Domain ID / Bus ID / location ID:   0 / 1 / 0
  Compute Mode:
     < Default (multiple host threads can use ::cudaSetDevice() with device simultaneously) >

deviceQuery, CUDA Driver = CUDART, CUDA Driver Version = 11.4, CUDA Runtime Version = 11.4, NumDevs = 1
Result = PASS

Why is it now mentioned CUDA version 11.4? Is it because I am using the NVIDIA_CUDA-11.4_Samples I guess?

Another information is the following. If I check in my /usr/local folder I see three folders related to CUDA.

If I do:

cd /usr/local && ll | grep -i CUDA

I get:

lrwxrwxrwx  1 root root   22 Oct  7 11:33 cuda -> /etc/alternatives/cuda/
lrwxrwxrwx  1 root root   25 Oct  7 11:33 cuda-11 -> /etc/alternatives/cuda-11/
drwxr-xr-x 16 root root 4096 Oct  7 11:33 cuda-11.4/

Is that normal?

Thanks for your help.