Unless your GPU and Graphics Driver was released before September 1, 2017, chances are almost certain that Vegas Pro 14 will not support hardware acceleration. That is when VP14 reached its EOL.
I don't think that is the case as NVIDIA drivers provide good backwards compatibility. The older benchmark in my signature has 30XX NVIDIA GPUs (2020 or newer) working with NVENC in VP 16 (ended July 2019)
Unless your GPU and Graphics Driver was released before September 1, 2017, chances are almost certain that Vegas Pro 14 will not support hardware acceleration. That is when VP14 reached its EOL.