OpenCV 4.5

Robotics & Edge Computing Jetson & Embedded Systems Jetson Xavier NX
5

It should be there. You may just check with:

sudo apt search cublas
Sorting... Done
Full Text Search... Done
libcublas-dev/unknown,stable,now 10.2.2.89-1 arm64 [installed,automatic]
  CUBLAS native dev links, headers

libcublas10/unknown,stable,now 10.2.2.89-1 arm64 [installed,automatic]
  CUBLAS native runtime libraries
...